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Journal articles on the topic '[3+2] cycloaddition reactions'

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Published: 5 June 2025

Last updated: 15 July 2025

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1

Grygorenko, Oleksandr O., Viktoriia S. Moskvina, Oleksandr V. Hryshchuk, and Andriy V. Tymtsunik. "Cycloadditions of Alkenylboronic Derivatives." Synthesis 52, no. 19 (2020): 2761–80. http://dx.doi.org/10.1055/s-0040-1707159.

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The literature on cycloaddition reactions of boron-containing alkenes is surveyed with 132 references. The data are categorized according to the reaction type ([2+1], [2+2], [3+2], [4+2], and [4+3] cycloadditions). The cyclopropanation and the Diels–Alder reactions of alkenylboronic derivatives have been studied more or less comprehensively, and for some substrates, they can be considered as convenient methods for the rapid regio- and stereoselective construction of even complex cyclic systems. Other types of the cycloadditions, as well as mechanistic aspects of the processes, have been addressed less thoroughly in the previous works.1 Introduction2 [2+1] Cycloaddition2.1 Cyclopropanation2.1.1 With Methylene Synthetic Equivalents2.1.2 With Substituted Carbenoids2.2 Epoxidation2.3 Aziridination3 [2+2] Cycloaddition4 [3+2] Cycloaddition4.1 With Nitrile Oxides4.2 With Diazoalkanes4.3 With Nitrones4.4 With Azomethine Ylides5 [4+2] Cycloaddition6 [4+3] Cycloaddition7 Conclusions and Outlook

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2

Asmita, Mondal, Banerji Avijit, and Acharjee Nivedita. "Understanding [3 + 2] cycloaddition reactions from the molecular electron density perspective : A new theoretical outlook on organic reactions." Education in Chemical Science and Technology Vol. 3, Aug 2022 (2022): 131–50. https://doi.org/10.5281/zenodo.6822007.

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Department of Chemistry, Durgapur Government College, Durgapur-713 214, West Bengal, India Central Ayurveda Research Institute (CARI), Calcutta-700 091, West Bengal, India E-mail: ablabcu@yahoo.co.uk Cycloaddition reactions share the top shelf priority in the toolbox of organic chemists owing to their diverse pharmaceutical and industrial applications. The frontiers molecular orbital (FMO) theory has been used to study the reactivity of cycloaddition reactions since nearly the last five decades, though there have been criticisms, and even instances of failures. In 2016, an appealing alternative has been proposed by Domingo, namely the molecular electron density theory (MEDT), to underline the decisive role of changes in electron density in the observed molecular reactivity of chemical reactions. MEDT uses a set of advanced quantum chemical tools and has been extensively applied to analyze organic reactions, particularly focussed on cycloadditions in more than 250 studies since last six years to cover varied aspects such as reactivity, substituent effects, catalysis, solvent effects, strain promotion, regio-, stereo- and chemoselectivity. This article is intended to present a brief overview of MEDT for analysis of [3 + 2] cycloaddition reactions by experimentalists and theoretical chemists.

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3

Winne, Johan, Jan Hullaert, Bram Denoo, Mien Christiaens, and Brenda Callebaut. "Heterocycles as Moderators of Allyl Cation Cycloaddition Reactivity." Synlett 28, no. 18 (2017): 2345–52. http://dx.doi.org/10.1055/s-0036-1588511.

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For the rapid elaboration of polycarbocyclic scaffolds, prevalent in many important families of terpenoid natural products, allyl cations derived from simple heterocyclic alcohols can be used as versatile reaction partners in both (4+3) and (3+2) cycloaddition pathways. Our recent progress in this area is outlined, pointing towards the untapped potential of heterocycles to act as reagents in novel or known but challenging organic transformations.1 Heterocyclic Reagents2 Cycloadditions and Allyl Cations3 Furfuryl Cations in Cycloadditions4 Heterocycle-Substituted Cations in Cycloadditions5 Mechanistic Considerations6 Conclusions and Outlook

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4

Dresler, Ewa, Aneta Wróblewska, and Radomir Jasiński. "Energetic Aspects and Molecular Mechanism of 3-Nitro-substituted 2-Isoxazolines Formation via Nitrile N-Oxide [3+2] Cycloaddition: An MEDT Computational Study." Molecules 29, no. 13 (2024): 3042. http://dx.doi.org/10.3390/molecules29133042.

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Regioselectivity and the molecular mechanism of the [3+2] cycloaddition reaction between nitro-substituted formonitrile N-oxide 1 and electron-rich alkenes were explored on the basis of the wb97xd/6-311+G(d) (PCM) quantum chemical calculations. It was established that the thermodynamic factors allow for the formation of stable cycloadducts along all considered models. The analysis of the kinetic parameters of the main processes show that all [3+2] cycloadditions should be realized with full regioselectivity. In all cases, the formation of 5-substituted 3-nitro-2-isoxazolidines is clearly preferred. It is interesting that regiodirection is not determined by the local electrophile/nucleophile interactions but by steric effects. From a mechanistic point of view, all considered reactions should be treated as polar, one-step reactions. All attempts to locate the hypothetical zwitterionic intermediates along the cycloaddition paths were, however, not successful.

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5

Harmata, Michael, and Aswin Garimalla. "Derivatives of Alkyl 2-Hydroxy-3-oxocyclopent-1-enecarboxylates and Intermolecular [4+2] Cycloadditions of Cyclopentadienones Prepared Therefrom." Synthesis 50, no. 22 (2018): 4483–89. http://dx.doi.org/10.1055/s-0037-1610184.

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Some derivatives of alkyl 2-hydroxy-3-oxocyclopent-1-enecarboxylates have been synthesized and their reactivity as progenitors of cyclopentadienones for intermolecular [4+2]-cycloaddition reactions has been evaluated. It was found that the derivative containing a phosphate ester leaving group gave better yields in the cycloaddition reaction among the derivatives studied. The yields of the cycloaddition reactions were moderate, perhaps due side reactions not leading to the reactive intermediate cyclopentadienone.

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6

Deng, Yongming, Qing-Qing Cheng, and Michael Doyle. "Asymmetric [3+3] Cycloaddition for Heterocycle Synthesis." Synlett 28, no. 14 (2017): 1695–706. http://dx.doi.org/10.1055/s-0036-1588453.

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Asymmetric syntheses of six-membered ring heterocycles are important research targets not only in synthetic organic chemistry but also in pharmaceuticals. The [3+3]-cycloaddition methodology is a complementary strategy to [4+2] cycloaddition for the synthesis of heterocyclic compounds. Recent progress in [3+3]-cycloaddition processes provide powerful asymmetric methodologies for the construction of six-membered ring heterocycles with one to three heteroatoms in the ring. In this account, synthetic efforts during the past five years toward the synthesis of enantioenriched six-membered ring heterocycles through asymmetric [3+3] cycloaddition are reported. Asymmetric organocatalysis uses chiral amines, thioureas, phosphoric acids, or NHC catalysis to achieve high enantiocontrol. Transition-metal catalysts used as chiral Lewis acids to activate a dipolar species is an alternative approach. The most recent advance, chiral transition-metal-catalyzed reactions of enoldiazo compounds, has contributed toward the versatile and highly selective synthesis of six-membered heterocyclic compounds.1 Introduction2 Asymmetric Formal [3+3]-Cycloaddition Reactions by Organocatalysis2.1 By Amino-Catalysis2.2 By N-Heterocyclic Carbenes2.3 By Bifunctional Tertiary Amine-thioureas2.4 By Chiral Phosphoric Acids3 Asymmetric Formal [3+3]-Cycloaddition Reactions by Transition-Metal Catalysis3.1 Copper Catalysis3.2 Other Transition-Metal Catalysis4 Asymmetric [3+3]-Cycloaddition Reactions of Enoldiazo Compounds4.1 Asymmetric [3+3]-Cycloaddition Reactions of Nitrones with Electrophilic Metallo-enolcarbene Intermediates4.2 Dearomatization in Asymmetric [3+3]-Cycloaddition Reactions of Enoldiazoacetates4.3 Asymmetric Stepwise [3+3]-Cycloaddition Reaction of Enoldiazoacetates with Hydrazones5 Summary and Outlook

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7

Li, Jin-Heng, De-Lie An, and Jing-Hao Qin. "Recent Advances in Cycloaddition Reactions with Alkynes to Construct Heterocycles." Synthesis 52, no. 24 (2020): 3818–36. http://dx.doi.org/10.1055/s-0040-1707355.

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Heterocyclic compounds, especially N-heterocycles and O-heterocycles, are prominent structural motifs present in numerous natural products and medically and/or economically important compounds. This review aims to describe the development of transition-metal-catalyzed cycloaddition reactions of functionalized m-atom partners with alkynes to access a wide range of five-, six-, and seven-membered heterocycles, that is functionalized N-heterocycles and O-heterocycles such as azepines, isoquinolines, isocoumarins, spiroheterocycles, indoles, furans, and pyrroles, in a selectively controlled manner with an emphasis on scope and limitations and with a discussion of the mechanisms.1 Introduction2 Intermolecular Cycloaddition To Construct Azepine Derivatives2.1 [5+2] Cycloaddition2.2 [3+2+2] Cycloaddition2.3 [3+2]/[5+2] Cycloaddition3 Intermolecular [4+2] Cycloaddition To Construct Isoquinolines or Isocoumarins4 Intermolecular [3+2] Cycloaddition To Construct Spiroheterocyclic Compounds, Indoles, Furans, and Pyrroles5 Summary and Outlook

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8

Sikervar, Vikas, Ravindra Sonawane, Raghuramaiah Mandadapu, Amol Satish Dehade, Shrikant Abhiman Shete, and Mark Montgomery. "Lewis Acid Mediated [3+2] and [3+3] Annulations of an Azomethine Imine with Donor–Acceptor Cyclopropanes." Synthesis 53, no. 16 (2021): 2865–73. http://dx.doi.org/10.1055/a-1503-8068.

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AbstractTwo different Lewis acids were used for developing [3+2] and [3+3] regioselective cycloaddition reactions of an azomethine imine with activated cyclopropanes. Scandium(III) triflate catalyzes a [3+2] cycloaddition reaction of the azomethine imine with cyclopropanes to form tetrahydropyrazolone derivatives and tricyclic tetrahydrofuran derivatives in moderate yields. Complementary to this, a novel [3+3] cycloaddition reaction of the azomethine imine with activated cyclopropanes was developed by using EtAlCl2 as a Lewis acid to form hexahydropyridazinone derivatives in high regioselectivity.

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9

Zhang, Xiaofeng, Xiaoming Ma, and Wei Zhang. "Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds." Beilstein Journal of Organic Chemistry 19 (November 6, 2023): 1677–93. http://dx.doi.org/10.3762/bjoc.19.123.

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The [3 + 2] cycloadditions of stabilized azomethine ylides (AMYs) derived from amino esters are well-established. However, the reactions of semi-stabilized AMYs generated from decarboxylative condensation of α-amino acids with arylaldehydes are much less explored. The [3 + 2] adducts of α-amino acids could be used for a second [3 + 2] cycloaddition as well as for other post-condensation modifications. This article highlights our recent work on the development of α-amino acid-based [3 + 2] cycloaddition reactions of N–H-type AMYs in multicomponent, one-pot, and stepwise reactions for the synthesis of diverse heterocycles related to some bioactive compounds and natural products.

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10

Li, Hui, Russell P. Hughes, and Jimmy Wu. "Dearomative Indole (3 + 2) Cycloaddition Reactions." Journal of the American Chemical Society 136, no. 17 (2014): 6288–96. http://dx.doi.org/10.1021/ja412435b.

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11

Frühauf, Hans-Werner. "Organotransition metal [3+2] cycloaddition reactions." Coordination Chemistry Reviews 230, no. 1-2 (2002): 79–96. http://dx.doi.org/10.1016/s0010-8545(01)00465-9.

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12

Sadowski, Mikołaj, Ewa Dresler, Karolina Zawadzińska, Aneta Wróblewska, and Radomir Jasiński. "Syn-Propanethial S-Oxide as an Available Natural Building Block for the Preparation of Nitro-Functionalized, Sulfur-Containing Five-Membered Heterocycles: An MEDT Study." Molecules 29, no. 20 (2024): 4892. http://dx.doi.org/10.3390/molecules29204892.

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The regio- and stereoselectivity and the molecular mechanisms of the [3 + 2] cycloaddition reactions between Syn-propanethial S-oxide and selected conjugated nitroalkenes were explored theoretically in the framework of the Molecular Electron Density Theory. It was found that cycloadditions with the participation of nitroethene as well as its methyl- and chloro-substituted analogs can be realized via a single-step mechanism. On the other hand, [3 + 2] cycloaddition reactions between Syn-propanethial S-oxide and 1,1-dinitroethene can proceed according to a stepwise mechanism with a zwitterionic intermediate. Finally, we evaluated the affinity of model reaction products for several target proteins: cytochrome P450 14α-sterol demethylase CYP51 (RSCB Database PDB ID: 1EA1), metalloproteinase gelatinase B (MMP-9; PDB ID: 4XCT), and the inhibitors of cyclooxygenase COX-1 (PDB:3KK6) and COX-2 (PDB:5KIR).

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13

MacKenzie, Douglas A., and John Paul Pezacki. "Kinetics studies of rapid strain-promoted [3+2] cycloadditions of nitrones with bicyclo[6.1.0]nonyne." Canadian Journal of Chemistry 92, no. 4 (2014): 337–40. http://dx.doi.org/10.1139/cjc-2013-0577.

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Strain-promoted alkyne−nitrone cycloaddition (SPANC) reactions represent a bioorthogonal labeling strategy that is both very rapid and at the same time efficient and selective. Nitrones provide increased reaction rates as well as greater susceptibility toward stereoelectronic modification when compared with organic azides. We find that strain-promoted cycloadditions of cyclic nitrones with bicyclo[6.1.0]nonyne react with second-order rate constants as large as 1.49 L mol−1 s−1 at 25 °C. These reactions display rate constants that are up to 37-fold greater than those of the analogous reactions of benzyl azide with bicyclo[6.1.0]nonyne. We observed that reactions of nitrones with bicyclo[6.1.0]nonyne showed a stronger dependence on substituent effect for the reaction, as evidenced by a larger Hammett ρ value, than that for biaryl-aza-cyclooctanone. We demonstrate the ability to stereoelectronically tune the reactivity of nitrones towards different cyclooctynes in SPANC reactions. This ability to introduce selectivity into different SPANC reactions through substituent provides the opportunity to perform multiple SPANC reactions in one reaction vessel and opens up potential applications in multiplex labeling.

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14

Antoci, Vasilichia, Costel Moldoveanu, Ramona Danac, Violeta Mangalagiu, and Gheorghita Zbancioc. "Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes." Molecules 25, no. 19 (2020): 4416. http://dx.doi.org/10.3390/molecules25194416.

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We present herein a straightforward and efficient pathway for the synthesis of pyrrolophthalazine cycloadducts via Huisgen [3 + 2] dipolar cycloaddition reactions of phthalazinium ylides to methyl propiolate or dimethyl acetylenedicarboxylate (DMAD). A thoroughly comparative study concerning the efficiency of synthesis, conventional thermal heating (TH) versus microwave (MW) and ultrasound (US) irradiation, has been performed. The cycloaddition reactions of phthalazinium ylides to methyl propiolate occur regiospecific, with a single regioisomer being obtained. Under conventional TH, the cycloaddition reaction of phthalazinium ylides with DMAD occurs to a mixture of inseparable partial and fully aromatized pyrrolophthalazine cycloadducts, while MW or US irradiation are leading only to fully aromatized compounds, with the reactions becoming selective. A feasible mechanism for formation of fully aromatized compounds is presented. Besides selectivity, it has to be noticed that the reaction setup under MW or US irradiation offer a number of other certain advantages: higher yields, decreasing of the amount of used solvent comparative with TH, decreasing of the reaction time from hours to minutes and decreasing of the consumed energy; consequently, these reactions could be considered environmentally friendly.

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15

WANG, JING-FANG, DONG-QING WEI, CHUN-FANG WANG, et al. "A THEORETICAL STUDY ON THE MECHANISM OF 2:1 1, 3 DIPOLAR CYCLOADDITION REACTIONS." Journal of Theoretical and Computational Chemistry 06, no. 04 (2007): 861–67. http://dx.doi.org/10.1142/s0219633607003489.

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The reactions between nitrile oxides and alkenes are of considerable interest in organic synthesis as the resulting heterocycles are versatile intermediates for the synthesis of natural products and biologically active compounds. In this paper, we design a series of reactions of phosphonyl nitrile oxides with acrylonnitrile, which can give 2:1 cycloaddition products with no crystal structure released so far, and present a detailed theoretical study on the mechanism of the 2:1 1, 3-dipolar cycloaddition reaction, which has been explored with density functional theory calculations at B3LYP/6-31G* level. The results reveal that the following mechanism is quite possible. Firstly, it starts as a normal 1,3-dipolar cycloaddition reaction to produce a regiospecific 1:1 product. Subsequently, highly reactive diisopropanyl phosphonyl nitrile oxide sequentially reacts with the aforementioned regiospecific 1:1 product and gives the corresponding cycloadduct. Further study is underway to expand the scope of this methodology, as well as to ascertain mechanistic details of the cycloaddition process.

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16

Mitka, Katarzyna, Katarzyna Fela, Aleksandra Olszewska, and Radomir Jasiński. "On the Question of Zwitterionic Intermediates in the [3 + 2] Cycloaddition Reactions between C-arylnitrones and Perfluoro 2-Methylpent-2-ene." Molecules 26, no. 23 (2021): 7147. http://dx.doi.org/10.3390/molecules26237147.

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The molecular mechanism of the [3 + 2] cycloaddition reaction between C-arylnitrones and perfluoro 2-methylpent-2-ene was explored on the basis of DFT calculations. It was found that despite the polar nature of the intermolecular interactions, as well as the presence of fluorine atoms near the reaction centers, all reactions considered cycloaddition proceed via a one-step mechanism. All attempts for the localization of zwitterionic intermediates on the reaction paths were not successful. Similar results were obtained regardless of the level of theory applied.

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17

Kuila, Bilash, Maninderjeet Kaur, Prabhpreet Singh, and Gaurav Bhargava. "Transition-Metal-Catalyzed [3+2+2] Cycloaddition Reactions." European Journal of Organic Chemistry 2018, no. 7 (2017): 853–68. http://dx.doi.org/10.1002/ejoc.201701116.

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18

Mlostoń, Grzegorz, Yuriy Shermolovich, and Heinz Heimgartner. "Synthesis of Fluorinated and Fluoroalkylated Heterocycles Containing at Least One Sulfur Atom via Cycloaddition Reactions." Materials 15, no. 20 (2022): 7244. http://dx.doi.org/10.3390/ma15207244.

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Fluorinated heterocycles constitute an important group of organic compounds with a rapidly growing number of applications in such areas as medicinal chemistry, agrochemicals production, polymer chemistry, as well as chemistry of advanced materials. In the latter case, fluorinated thiophenes are considered as a lead class of compounds with numerous spectacular applications. On the other hand, cycloaddition reactions offer a superior methodology for stereo-chemically controlled synthesis of heterocycles with a diverse ring size and a variable number of heteroatoms. A comprehensive review of methods based on cycloaddition reactions and applied for construction of fluorinated and/or fluoroalkylated S-heterocycles has not yet been published. For this reason, the main goal of the presented review was to fill the existing gap and to summarize the results published over last six decades. In this context, the [3+2]- and [4+2]-cycloadditions (Huisgen reactions, and Diels–Alder reactions, respectively) are of special importance. Some questions related to the discussed mechanisms of cycloaddition processes observed in reactions with electron deficient, fluorinated substrates (dipolarophiles and dienophiles), and electron-rich sulfur containing counter partners, are of fundamental importance for the development of interpretations of organic reaction mechanisms.

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19

Engler, Thomas A., Cynthia M. Scheibe, and Rajesh Iyengar. "Tandem 5 + 2/3 + 2 and 5 + 2/3 + 3 Cycloaddition Reactions." Journal of Organic Chemistry 62, no. 24 (1997): 8274–75. http://dx.doi.org/10.1021/jo971601k.

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20

Wu, Jimmy, and Hui Li. "(3+2)-Cycloaddition Reactions of Oxyallyl Cations." Synthesis 47, no. 01 (2014): 22–33. http://dx.doi.org/10.1055/s-0034-1378918.

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21

Kuznetsov, Maksim L. "Theoretical studies on [3+2]-cycloaddition reactions." Russian Chemical Reviews 75, no. 11 (2006): 935–60. http://dx.doi.org/10.1070/rc2006v075n11abeh001195.

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22

Salem, Mohammed A., Moustafa A. Gouda, and Ghada G. El-Bana. "Chemistry of 2-(Piperazin-1-yl) Quinoline-3-Carbaldehydes." Mini-Reviews in Organic Chemistry 19, no. 4 (2022): 480–95. http://dx.doi.org/10.2174/1570193x18666211001124510.

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Abstract: This review described the preparation of 2- chloroquinoline-3-carbaldehyde derivatives 18 through Vilsmeier-Haack formylation of N-arylacetamides and the use of them as a key intermediate for the preparation of 2-(piperazin-1-yl) quinoline-3-carbaldehydes. The synthesis of the 2- (piperazin-1-yl) quinolines derivatives was explained through the following chemical reactions: acylation, sulfonylation, Claisen-Schmidt condensation, 1, 3-dipolar cycloaddition, one-pot multicomponent reactions (MCRs), reductive amination, Grignard reaction and Kabachnik-Field’s reaction.

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23

Sosnovskikh, Vyacheslav Y. "Synthesis and Reactivity of Electron-Deficient 3-Vinylchromones." SynOpen 05, no. 03 (2021): 255–77. http://dx.doi.org/10.1055/a-1589-9556.

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AbstractThe reported methods and data for the synthesis and reactivity of electron-deficient 3-vinylchromones containing electron-withdrawing groups at the exo-cyclic double bond are summarized and systematized for the first time. The main methods for obtaining these compounds are Knoevenagel condensation, Wittig reaction, and palladium-catalyzed cross-couplings. The most important chemical properties are transformations under the action of mono- and dinucleophiles, ambiphilic cyclizations, and cycloaddition reactions. The cross-conjugated and polyelectrophilic dienone system in 3-vinylchromones provides their high reactivity and makes these compounds valuable building blocks for the preparation of more complex heterocyclic systems. Chemical transformations of 3-vinylchromones usually begin with an attack of the C-2 atom and are accompanied by the opening of the pyrone ring followed by recyclization, in which the carbonyl group of chromone, an exo-double bond or a substituent on it can take part. The mechanisms of the reactions are discussed, the conditions for their implementation are described, and the yields of the resulting products are given. This review focuses on an analysis and generalization of the knowledge that has accumulated on the chemistry of electron-deficient 3-vinylchromones, mostly over the past 15 years.1 Introduction2 Synthesis of 3-Vinylchromones3 Reactions with Mononucleophiles4 Reactions with Dinucleophiles5 Ambiphilic Cyclization6 Cycloaddition Reactions7 Other Reactions8 Conclusion

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24

Jasiński, Radomir, Magda Ziółkowska, Oleh Demchuk, and Agata Maziarka. "Regio- and stereoselectivity of polar [2+3] cycloaddition reactions between (Z)-C-(3,4,5-trimethoxyphenyl)-N-methylnitrone and selected (E)-2-substituted nitroethenes." Open Chemistry 12, no. 5 (2014): 586–93. http://dx.doi.org/10.2478/s11532-014-0518-2.

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Abstract[2+3] Cycloaddition reactions of the highly reactive (Z)-C-(3,4,5-trimethoxyphenyl)-N-methylnitrone with (E)-2-R-nitroethenes proceed under mild conditions and yield mixtures of stereoisomeric 2-methyl-3-(3,4,5-trimethoxyphenyl)-4-nitro-5-R-isoxazolidines. The effect of regiospecificity of the cycloadditions may be accounted for by the theory of electrophilicity indexes. Stereoselectivity, however, is determined by a compilation of steric and secondary orbital effects.

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25

Wiberg, N., G. Preiner, G. Wagner, and H. Köpf. "Reaktivität des labilen, durch Adduktbildung mit Ph2C=NSiMe3 gespeicherten Silaethens Me2Si=C(SiMe3)2 / Reactivity of the Labile Silaethene Me2Si = C(SiMe3)2, Stored as Ph2C =NSiMe3 Adducts." Zeitschrift für Naturforschung B 42, no. 9 (1987): 1062–74. http://dx.doi.org/10.1515/znb-1987-0902.

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Silaethene Me2Si = C(SiMe3)2 (1), stored as Ph2C=NSiMe3 adducts and regenerated from the adducts at about 100 °C as a reaction intermediate, combines with reactants a-b (e. g. HO-H, RO-H. RCOO-H, RS-H. RHN-H, Ph2CN-H, RO-SiR3, R2N-SiR3, Ph2CN-SiR3, Cl-GeR3, Cl-SnR3) with insertion into the a-b bond, with a=b (e.g. 0 = CPh2, Me3SiN = CPh2, CH2=CHOMe, cis-piperylene), a=b=c (e.g. RN = N = N, O = N=N). a=b-c=d (e.g. butadiene, isoprene, trans-piperylene, 2,3-dimethylbutadiene, cyclopentadiene, anthracene, benzophenone, N-trimethylsilylbenzophenoneimine) under [2+2]-, [2+3]- as well as [2+A]-cycloaddition and with a=b-c-H (e.g. propene, butenes, isoprene. 2.3-dimethylbutadiene, acetone) under ene reaction. According to relative reaction rates, insertion and [2+2]-cycloadditions seem to proceed in two reaction steps, whereas [2+4]-cycloadditions and ene reactions with organic dienes and enes obviously are one step reactions. For relative reactivities cf. Table I.

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26

Gulías, Moisés, Fernando López, and José L. Mascareñas. "Development of transition-metal-catalyzed cycloaddition reactions leading to polycarbocyclic systems." Pure and Applied Chemistry 83, no. 3 (2011): 495–506. http://dx.doi.org/10.1351/pac-con-10-10-23.

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We present a compilation of methodologies developed in our laboratories to assemble polycyclic structures containing small- and medium-sized cycles, relying on the use of transition-metal-catalyzed (TMC) cycloadditions. First, we discuss the use of alkylidenecyclopropanes (ACPs) as 3C-atom partners, in particular in their Pd-catalyzed (3 + 2) cycloadditions with alkynes, alkenes, and allenes, reactions that lead to cyclopentane-containing polycyclic products in excellent yields. Then, we present the expansion of this chemistry to a (4 + 3) annulation with conjugated dienes, and to inter- and intramolecular (3 + 2 + 2) cycloadditions using external alkenes as additional 2C-π-systems. These reactions allow the preparation of different types of polycyclic structures containing cycloheptene rings, the topology of the products depending on the use of Pd or Ni catalysts. Finally, we include our more recent discoveries on the development of (4 + 3) and (4 + 2) intramolecular cyclo-additions of allenes and dienes, promoted by Pt and Au catalysts, and discuss mechanistic insights supported by experimental and density functional theory (DFT) calculations. An enantioselective version of the (4 + 2) cycloaddition with phosphoramidite Au(I) catalysts is also presented.

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27

Choi, Cheol Ho, and Mark S. Gordon. "Cycloaddition Reactions of Dienes on the SI(100)-2 × 1 Surface." International Journal of Modern Physics B 17, no. 08n09 (2003): 1205–10. http://dx.doi.org/10.1142/s0217979203018752.

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Quantum mechanical methods were adopted to study the surface reaction mechanisms of 1, 3-cyclohexadiene and acrylonitrile on the Si(100)-2x1 surface. According to the computed potential energy surfaces, both ⌊4+2⌋ and ⌊2+2⌋ cycloaddition products resulting from the reactions of surface dimers are possible due to the negligible activation barriers at the surface. Isomerization reactions among the surface products are very unlikely due to the predicted large activation barriers preventing thermal redistributions of the surface products. As a result, the distribution of the final surface products is kinetically controlled leading to a reinterpretation of recent experiments. An intermediate Lewis acid-base type complex appears in both the ⌊4+2⌋ and ⌊2+2⌋ cycloadditions of acrylonitrile entrance channels, indicating that the surface may act as an electrophile/Lewis acid towards a strong Lewis base substrate.

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28

Ogurtsov, Vladimir A., and Oleg A. Rakitin. "New Cycloadditon Reaction of 2-Chloroprop-2-enethioamides with Dialkyl Acetylenedicarboxylates: Synthesis of Dialkyl 2-[4,5-Bis(alkoxycarbonyl)-2-(aryl{alkyl}imino)-3(2H)-thienylidene]-1,3-dithiole-4,5-dicarboxylates." Molecules 27, no. 20 (2022): 6887. http://dx.doi.org/10.3390/molecules27206887.

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The 1,3-dipolar cycloaddition of 1,2-dithiole-3-thiones with alkynes to form 1,3-dithioles is one of the most studied reactions in this class of polysulfur-containing heterocycles. Nucleophilic substitution of chlorine atoms in dimethyl 2-(1,2-dichloro-2-thioxoethylidene)-1,3-dithiole-4,5-dicarboxylate, which was obtained by addition one molecules of DMAD to 4,5-dichloro-3H-1,2-dithiole-3-thione, led to a series of 2-chloro-2-(1,3-dithiol-2-ylidene)ethanethioamides. Cycloaddition reaction of 2-chloro-2-(1,3-dithiol-2-ylidene)ethanethioamides with activated alkynes led to the unexpected formation of 2-(thiophen-3(2H)-ylidene)-1,3-dithioles via new intermediate, 1-(1,3-dithiol-2-ylidene)-N-phenylethan-1-yliumimidothioate. Structure of dimethyl2-(4,5-bis(methoxycarbonyl)-2-(phenylimino)thiophen-3(2H)-ylidene)-1,3-dithiole-4,5-dicarboxylate was finally proven by single crystal X-ray diffraction study. Optimized reaction conditions and a mechanistic rationale for the 1,3-dipolar cycloaddition of novel intermediate are presented.

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29

Patrick, Timothy B., Mehrdad Shadmehr, Akbar H. Khan, Rajiv K. Singh, and Bethel Asmelash. "[3+2] Cycloaddition reactions of diethyl (E)-2-fluoromaleate." Journal of Fluorine Chemistry 143 (November 2012): 109–11. http://dx.doi.org/10.1016/j.jfluchem.2012.04.015.

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30

Zhan, Desheng, Gang Yang, Tieli Zhou, Sashirekha Nallapati, and Xiaofeng Zhang. "Decarboxylation-Driven Double Annulations: Innovative Multi-Component Reaction Pathways." Molecules 30, no. 7 (2025): 1594. https://doi.org/10.3390/molecules30071594.

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A concerted five-component reaction strategy has been developed, featuring double [3+2] cycloadditions utilizing aspartic acid. This approach provides valuable insights into mechanistic pathways, allowing for the distinction between concerted and stepwise processes based on reaction efficiency and diastereoselectivity. Both aspartic and glutamic acids have been employed for a thorough evaluation and exploration of decarboxylation-driven double annulations. This method effectively constructs pyrrolizidine frameworks through a concerted double 1,3-dipolar cycloaddition with aspartic acid, as well as tetrahydropyrrolizinones via three-component double annulations, which include decarboxylative 1,3-dipolar cycloaddition and lactamization with glutamic acid. These highly convergent, decarboxylation-driven multicomponent reactions (MCRs) efficiently produce fused polyheterocyclic systems while being environmentally friendly, generating only CO2 and water as byproducts.

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31

Stevens, Katelyn, Shik Ki Li, Emily Kaufman, et al. "Initial Examinations of the Diastereoselectivity and Chemoselectivity of Intramolecular Silyl Nitronate [3+2] Cycloadditions with Alkenyl/Alkynyl Nitroethers." Molecules 29, no. 24 (2024): 5816. https://doi.org/10.3390/molecules29245816.

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This study examined the chemoselectivity and diastereoselectivity of silyl nitronate alkenyn-nitroethers in Intramolecular Silyl Nitronate Cycloadditions (ISNCs) to produce isoxazole derivatives with interesting medicinal properties. These reactions resulted in the formation of either dihydrofuro[3,4-c]isoxazolines/isoxazolidines and/or alkynyl moieties attached to 2,5-dihydrofuryl carbonyls. This study also discerned the diastereoselectivities of the resulting cyclic adducts and compared them to previous findings. The reactions were also investigated with Spartan molecular modeling computations to aid in the understanding of any displayed chemo- and/or stereoselectivity. These [3+2]-cycloaddition reactions demonstrated excellent to complete chemospecificity. The cycloadditions also demonstrated remarkable diastereospecificity in that each diastereomer of the nitroethers resulted in the formation of only one of four possible diastereomeric outcomes. The stereochemistry of the major diastereomers did not agree with previously published findings.

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32

Li, Dan, Wei Gao, and Xiaochao Chen. "Asymmetric Synthesis of C1-Chiral THIQs with Imines in Isoquinoline Rings." Synthesis 52, no. 22 (2020): 3337–55. http://dx.doi.org/10.1055/s-0040-1707206.

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Tetrahydroisoquinoline (THIQ) scaffolds are important structural units that widely exist in a variety of natural alkaloids and synthetic analogues. Asymmetric synthesis of C1-chiral THIQ is of particular importance due to its significant pharmaceutical, agrochemical, and other biological activities, and the usually distinct bioactivities exhibited by the two enantiomers. In this review, we highlight the significant advances achieved in this field, present recent asymmetric synthesis with imines in isoquinoline rings ordered according to the sequence of various substrate types. New strategies could be inspired and more types of substrates need further development.1 Introduction2 Catalytic Asymmetric Reaction of Dihydroisoquinolines2.1 Asymmetric Reactions of 3,4-Dihydroisoquinolines2.2 Asymmetric Reactions of Dihydroisoquinolinium Salts2.3 Asymmetric Reactions of C,N-Cyclic N′-Acyl Azomethine Imines2.3.1 NED [3+2] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.2 IED [3+2] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.3 [3+3] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.4 [4+3] Cycloaddition of C,N-Cyclic N′-Acyl Azomethine Imines2.3.5 Asymmetric Addition Reactions to C,N-Cyclic N′-Acyl Azomethine Imines2.4 Asymmetric Reactions of C,N-Cyclic Nitrones3 Catalytic Asymmetric Mannich Reactions of Isoquinolines4 Conclusions and Perspectives

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33

Ryachi, Kamal, Ali Barhoumi, Mhamed Atifa, et al. "Molecular docking, elucidating the regiospecificity and the mechanism of [3+2] cycloloaddition reaction between azidobenzene and propiolaldehyde." Current Chemistry Letters 13, no. 2 (2024): 303–14. http://dx.doi.org/10.5267/j.ccl.2023.12.002.

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Molecular electron density theory has been performed with the B3LYP/6-31(d,p) method to study the [3+2] cycloaddition processes between azidobenzene and propionaldehyde, the reactivity indices, activation and reaction energies are computed. The reaction and activation energies indicate that this [3+2] cycloaddition reaction is regiospecific, in good agreement with the experimental results. ELF examination revealed that the mechanism of these cycloaddition reactions takes place in two steps. In addition, a docking approach was performed on the products investigated, and the interaction with the protein protease COVID-19 (PDB ID: 6LU7), the results confirm that the presence of triazole and isoxazole rings increases the affinity of these products.

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34

Corti, Vasco, Enrico Marcantonio, Martina Mamone, Alessandro Giungi, Mariafrancesca Fochi, and Luca Bernardi. "Synergistic Palladium-Phosphoric Acid Catalysis in (3 + 2) Cycloaddition Reactions between Vinylcyclopropanes and Imines." Catalysts 10, no. 2 (2020): 150. http://dx.doi.org/10.3390/catal10020150.

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The palladium-catalyzed (3 + 2) cycloaddition reaction between vinylcyclopropanes (VCPs) bearing geminal EWG’s and imines represents a straightforward and flexible entry to polysubstituted pyrrolidine derivatives. In this paper, we demonstrate that using a synergistic catalysis approach, based on the combination of phosphoric acid and palladium catalysts, it is possible to engage for the first time N-aryl and N-benzyl imines in this cycloaddition reaction. A range of polysubstituted pyrrolidines is obtained with moderate to good yields and diastereoselectivities, using a simple palladium species (Pd(PPh3)4) and an archetypical phosphoric acid as catalyst combination. A two-step scheme which exploits the same palladium catalyst for two consecutive and mechanistically distinct reactions (the cycloaddition and a Suzuki–Miyaura cross-coupling) is also presented. This synergistic catalysis approach is well posited for the development of the enantioselective version of this reaction. A screening of common BINOL-derived chiral phosphoric acids as catalyst component identified a species giving the product with moderate, yet promising, enantioselectivity (64% ee).

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35

G.A, AHMED. "[4+2]Cycloaddition Reactions and other Reactions of 2-(Sulphinylamino )thiazole." Journal of Indian Chemical Society Vol. 72, Aug 1995 (1995): 525–27. https://doi.org/10.5281/zenodo.5908800.

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Chemistry Department , Faculty of Science, Zagazig University, Zagazig, Egypt <em>Manuscript received 3 September 1993, revised 17 January 1994. accepted 18 February 1994</em> 2-(Sulphinylamino)thiozole (I) on reaction with some dienes under Diels-Aider condition gave the [4+2]cycloaddition products (2a,b). Compound 1 also underwent reaction with nitrile oxide to form 3<em>H</em>-1,2,3,5- oxatbiadiuzole-2-oxide (3). The reactivity of 1 towards active methylene compounds was studied. Some Schiff buses (5a-c) were obtained by the reaction of 1 with aromatic aldehydes. Further, the reaction of 1 with copper and sodium metals, produced azo and thiazo products 6 and 7 respectively.

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36

Schienebeck, Casi M., Xiaoxun Li, Xing-zhong Shu, and Weiping Tang. "3-Acyloxy-1,4-enyne: A new five-carbon synthon for rhodium-catalyzed [5 + 2] cycloadditions." Pure and Applied Chemistry 86, no. 3 (2014): 409–17. http://dx.doi.org/10.1515/pac-2014-5042.

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Abstract Seven-membered rings are ubiquitous in natural products and pharmaceutical agents, and their syntheses continue to stimulate the development of novel synthetic methods. The [5 + 2] cycloaddition is one of the most efficient ways to access seven-membered rings since the two-carbon components (alkenes, alkynes, or allenes) are readily available. Prior to our study, however, there was only one type of transition-metal-catalyzed [5 + 2] cycloaddition: the reaction between vinylcyclopropanes and alkenes, alkynes, or allenes. We recently developed a new type of transition-metal-catalyzed [5 + 2] cycloaddition, where the five-carbon building block is 3-acyloxy-1,4-enyne (ACE). Our recent progress on Rh-catalyzed intra- and intermolecular [5 + 2] cycloadditions of ACEs and alkynes is summarized in this article. Using chiral propargylic esters, bicyclic products were prepared in high optical purity by the intramolecular [5 + 2] cycloadditions. Monocyclic seven-membered rings were synthesized by intermolecular [5 + 2] cycloaddition of ACEs and alkynes. Kinetic studies indicated that the rate of this intermolecular cycloaddition was significantly accelerated when the acetate was replaced by dimethylaminobenzoate. DFT calculations suggested that novel metallacycles were generated by a Rh-promoted oxidative cycloaddition of 1,4-enynes accompanied by a 1,2-acyloxy migration of propargylic esters.

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37

Tupychak, M., N. Pokhodylo, and M. Obushak. "3-Aryl-2-azidopropanoic acids in cycloaddition reactions." Visnyk of the Lviv University. Series Chemistry 63, no. 1 (2022): 217. http://dx.doi.org/10.30970/vch.6301.217.

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38

Trost, Barry M., James P. Stambuli, Steven M. Silverman, and Ulrike Schwörer. "Palladium-Catalyzed Asymmetric [3 + 2] Trimethylenemethane Cycloaddition Reactions." Journal of the American Chemical Society 128, no. 41 (2006): 13328–29. http://dx.doi.org/10.1021/ja0640750.

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39

Wang, Dong-Chao, Ming-Sheng Xie, Hai-Ming Guo, Gui-Rong Qu, Meng-Cheng Zhang, and Shu-Li You. "Enantioselective Dearomative [3+2] Cycloaddition Reactions of Benzothiazoles." Angewandte Chemie International Edition 55, no. 45 (2016): 14111–15. http://dx.doi.org/10.1002/anie.201607852.

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40

Wang, Dong-Chao, Ming-Sheng Xie, Hai-Ming Guo, Gui-Rong Qu, Meng-Cheng Zhang, and Shu-Li You. "Enantioselective Dearomative [3+2] Cycloaddition Reactions of Benzothiazoles." Angewandte Chemie 128, no. 45 (2016): 14317–21. http://dx.doi.org/10.1002/ange.201607852.

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41

Li, Hui, Russell P. Hughes, and Jimmy Wu. "ChemInform Abstract: Dearomative Indole [3 + 2] Cycloaddition Reactions." ChemInform 45, no. 46 (2014): no. http://dx.doi.org/10.1002/chin.201446147.

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42

Zhou, Tao, Bin Li, and Baiquan Wang. "Rhodium-catalyzed C2 and C4 C–H activation/annulation of 3-(1H-indol-3-yl)-3-oxopropanenitriles with internal alkynes: a facile access to substituted and fused carbazoles." Chemical Communications 53, no. 47 (2017): 6343–46. http://dx.doi.org/10.1039/c7cc02808c.

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Rhodium-catalyzed C2 and C4 C–H activation/annulation of 3-(1H-indol-3-yl)-3-oxopropanenitriles with internal alkynes has been developed. Substituted and fused carbazole derivatives were obtained through formal rhodium-catalyzed (4+2) or tandem (4+2) and (5+2) cycloaddition reactions under mild reaction conditions in good yields.

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43

Jia, Qianfa, Zhiyun Du, Kun Zhang, and Jian Wang. "[3 + 2] Cycloaddition of aza-oxyallyl cations with aldehydes." Organic Chemistry Frontiers 4, no. 1 (2017): 91–94. http://dx.doi.org/10.1039/c6qo00526h.

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44

Zawadzińska, Karolina, та Karolina Kula. "Application of β-Phosphorylated Nitroethenes in [3+2] Cycloaddition Reactions Involving Benzonitrile N-Oxide in the Light of a DFT Computational Study". Organics 2, № 1 (2021): 26–37. http://dx.doi.org/10.3390/org2010003.

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The regiochemistry of [3+2] cycloaddition (32CA) processes between benzonitrile N-oxide 1 and β-phosphorylated analogues of nitroethenes 2a–c has been studied using the Density Functional Theory (DFT) at the M062X/6-31+G(d) theory level. The obtained results of reactivity indices show that benzonitrile N-oxide 1 can be classified both as a moderate electrophile and moderate nucleophile, while β-phosphorylated analogues of nitroethenes 2a–c can be classified as strong electrophiles and marginal nucleophiles. Moreover, the analysis of CDFT shows that for [3+2] cycloadditions with the participation of β-phosphorylatednitroethene 2a and β-phosphorylated α-cyanonitroethene 2b, the more favored reaction path forms 4-nitro-substituted Δ2-isoxazolines 3a–b, while for a reaction with β-phosphorylated β-cyanonitroethene 2c, the more favored path forms 5-nitro-substituted Δ2-isoxazoline 4c. This is due to the presence of a cyano group in the alkene. The CDFT study correlates well with the analysis of the kinetic description of the considered reaction channels. Moreover, DFT calculations have proven the clearly polar nature of all analyzed [3+2] cycloaddition reactions according to the polar one-step mechanism.

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45

Liu, Wentong, Yi Kuang, Zhifan Wang, Jin Zhu, and Yuanhua Wang. "Dirhodium(II)-catalyzed [3 + 2] cycloaddition of N-arylaminocyclopropane with alkyne derivatives." Beilstein Journal of Organic Chemistry 15 (February 25, 2019): 542–50. http://dx.doi.org/10.3762/bjoc.15.48.

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Dirhodium(II) complex-catalyzed [3 + 2] reactions between N-arylaminocyclopropanes and alkyne derivatives are described. The cycloaddition products proved to be versatile synthetic intermediates. trans-Cyclic β-amino acids and derivatives thereof can be conveniently synthesized using this cycloaddition protocol.

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46

Burger, Klaus, Eva Höß, Norbert Sewald, Klaus Geith, Jürgen Riede, and Peter Bissinger. "Zum Cycloadditionsverhalten von 5-Azido-4-trifluormethyl-1,3-azolen / Cycloaddition Reactions with 5-Azido-4-trifluoromethyl-1,3-azoles." Zeitschrift für Naturforschung B 45, no. 12 (1990): 1695–708. http://dx.doi.org/10.1515/znb-1990-1217.

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[3+2] Cycloaddition reactions of 5-azido-4-trifluoromethyl-1,3-azoles with various CC multiple bond systems are described. On reaction of 5-azido-4-trifluoromethylthiazoles 2 with 2,3-dimethylbuta-1,3-diene no [3+2] cycloaddition products could be isolated, 5,6-dihydro-2 H-pyrane 19 was formed exclusively. Photolysis of 1,2,3-triazoles 23, 24, obtained from 2 and electron deficient alkynes, yields imidazo[5,1-b]thiazoles 28. This photoreaction can be interpreted mechanistically as a “Thio-Cornforth-Reaction”.

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47

ENGLER, T. A., C. M. SCHEIBE, and R. IYENGAR. "ChemInform Abstract: Tandem [5 + 2]/[3 + 2] and [5 + 2]/[3 + 3] Cycloaddition Reactions." ChemInform 29, no. 27 (2010): no. http://dx.doi.org/10.1002/chin.199827031.

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48

Lee, Hee-Yoon, Seog-Beom Song, Taek Kang, Yoon Jung Kim, and Su Jeong Geum. "Aziridinyl imines in organic synthesis: Development of tandem reaction strategies and application to total synthesis of natural products." Pure and Applied Chemistry 85, no. 4 (2013): 741–53. http://dx.doi.org/10.1351/pac-con-12-10-01.

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Aziridinyl imines are well-known carbene equivalents because they are precursors of diazo compounds from which reactive intermediates can be produced. These carbene equivalents can be utilized as zwitterionic species, diradicals, or 4π system for cycloaddition reactions. Thus, the intermediates derived from aziridinyl imines have been used in the sulfur-ylide-mediated epoxide formation, tandem free-radical reactions, or cyclopropanation reaction via carbene intermediates to form trimethylenemethane (TMM) diyls, which undergo [2 + 3] cycloaddition reactions to form cyclopentanoids. Diazo compounds generated from aziridinyl imines also react with allenes to form TMM diyls. This reaction was utilized in tandem cycloaddition reactions of linear substrates to form polyquinanes. These tandem reaction strategies were successfully applied to the total synthesis of various cyclopentanoid natural products.

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49

Petko, Dina, Samuel Koh, and William Tam. "Transition Metal-Catalyzed Reactions of Alkynyl Halides." Current Organic Synthesis 16, no. 4 (2019): 546–82. http://dx.doi.org/10.2174/1570179416666190329200616.

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Background: Transition metal-catalyzed reactions of alkynyl halides are a versatile means of synthesizing a wide array of products. Their use is of particular interest in cycloaddition reactions and in constructing new carbon-carbon and carbon-heteroatom bonds. Transition metal-catalyzed reactions of alkynyl halides have successfully been used in [4+2], [2+2], [2+2+2] and [3+2] cycloaddition reactions. Many carbon-carbon coupling reactions take advantage of metal-catalyzed reactions of alkynyl halides, including Cadiot-Chodkiewicz, Suzuki-Miyaura, Stille, Kumada-Corriu and Inverse Sonogashira reactions. All the methods of constructing carbon-nitrogen, carbon-oxygen, carbon-phosphorus, carbon-sulfur, carbon-silicon, carbon-selenium and carbon-tellurium bonds employed alkynyl halides. Objective: The purpose of this review is to highlight and summarize research conducted in transition metalcatalyzed reactions of alkynyl halides in recent years. The focus will be placed on cycloaddition and coupling reactions, and their scope and applicability to the synthesis of biologically important and industrially relevant compounds will be discussed. Conclusion: It can be seen from the review that the work done on this topic has employed the use of many different transition metal catalysts to perform various cycloadditions, cyclizations, and couplings using alkynyl halides. The reactions involving alkynyl halides were efficient in generating both carbon-carbon and carbonheteroatom bonds. Proposed mechanisms were included to support the understanding of such reactions. Many of these reactions face retention of the halide moiety, allowing additional functionalization of the products, with some new products being inaccessible using their standard alkyne counterparts.

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50

Suárez-Rodríguez, Tatiana, Angel Luis Suárez-Sobrino, and Alfredo Ballesteros. "Gold(I)-Catalyzed [8+2]-Cycloaddition of 8-Aryl-8-azaheptafulvenes with Allenamides and Ynamides: Regioselective Synthesis of Dihydrocycloheptapyrrole Derivatives." Chemistry-A European Journal 27 (February 10, 2021): 7154–59. https://doi.org/10.1002/chem.202005348.

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Gold(I)-catalyzed higher-order [8+2] cycloadditions of 8-aryl-8-azaheptafulvenes 1 with allenamides 2 and ynamides 3 were studied. 1,8–Dihydrocycloheptapyrroles 4 were achieved by a regioselective [8+2] cycloaddition of azaheptafulvenes 1 and allenamides 2 in the presence of (2,4–ditBuC6H3O)3PAuNTf2 as catalyst. Besides, ynamides 3 and 8–aryl-8–azaheptafulvenes 1, undergo a regioselective [8+2] cycloaddition, to give 2-amido-1,4-dihydrocycloheptapyrroles 7 in the presence of JohnPhosAuNTf2 ascatalyst. Both reactions take place with good yields and with a variety of substituents. A plausible mechanism hypothesis suggests a nucleophilic attack of the 8-azaheptafulvene to the gold activated electron rich allene or alkyne moieties of the allenamide and ynamide respectively.

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