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Relevant bibliographies by topics / Amide de Weinreb

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Academic literature on the topic 'Amide de Weinreb'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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Journal articles on the topic "Amide de Weinreb"

1

Khalid, Maher, and Shireen Mohammedand Amin Kalo. "Recent Developments in Weinreb Synthesis and Their Applications." Oriental Journal of Chemistry 35, no. 6 (2019): 1611–26. http://dx.doi.org/10.13005/ojc/350601.

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N-methoxy-N-methyl amides or Weinreb amides are worthy embranchment of amide group and their rich functional groups in organic synthesis become a strong else unfeasible conversion. Weinreb amides are produced as an intermediate product of the reaction of carboxylic acids, acid chloride or esters with organometallic reagents, which was first uncovered in 1981. The direct conversion of carboxylic acids or acid chlorides or esters to ketones or aldehydes using organometallic reagents do not lead in high yields, because the intermediate ketones are still highly reactive toward the organometallic reagent. However, after derivatization to the corresponding Weinreb Amide, reaction with organometallics does give the desired ketones, as the initial adduct is stabilized and doesn't undergo further reactions. A nucleophilic addition to the Weinreb amides results in a unique and stable five-membered cyclic tetrahedral intermediate which protects the over-addition, leading to a selective conversion.

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2

Senatore, Raffaele, Laura Ielo, Serena Monticelli, Laura Castoldi та Vittorio Pace. "Weinreb Amides as Privileged Acylating Agents for Accessing α-Substituted Ketones". Synthesis 51, № 14 (2019): 2792–808. http://dx.doi.org/10.1055/s-0037-1611549.

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The acylation of α-substituted carbanion-type reagents (MCR1R2X; X = halogen, OR, SR, NR3R4, SeR, etc.) with Weinreb amides constitutes a highly versatile and flexible approach for accessing α-functionalized ketones. In this short review we will present a series of transformations—from our own and the work of others—documenting the general applicability of the methodology. Chemoselectivity is uniformly manifested including for critical substrates featuring additional electrophilic functionalities or sterically demanding elements. Importantly, the stereochemical information contained in the Weinreb amides can be fully transferred to the targeted ketones without affecting the optical purity. The protocol is also applicable to chiral carbanions generated through sparteine-mediated asymmetric deprotonation: the careful design of the experimental procedure allows recycling of the sparteine and the Weinreb ‘amine’ (N,O-dimethylhydroxylamine), thus improving the sustainability perspective of the processes.1 Introduction1.1 The Problem of the Synthesis of α-Substituted Ketones1.2 Weinreb Amides: General Features and Preparation2 Synthesis of α-Substituted Ketones2.1 α-Haloketones2.2 Synthesis of α-Cyanoketones2.3 Synthesis of α-Oxyketones2.4 Synthesis of β-Oxo Thioethers (α-Thioketones)2.5 Synthesis of Chiral α-Oxy and α-Nitrogen Ketones via the Sparteine-Mediated Generation of Optically Active Organolithiums2.6 Synthesis of α-Selenomethyl Ketones2.7 Reactivity of α-Phosphorus Carbanions with Weinreb Amides2.8 Modification of the Weinreb Amide Core: The CLAmP Reagent3 Competing Attack of Nucleophiles at More Reactive Electrophilic Sites than Weinreb Amides4 Conclusions

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Asahara, Haruyasu, Keita Arikiyo, and Nagatoshi Nishiwaki. "Development of variously functionalized nitrile oxides." Beilstein Journal of Organic Chemistry 11 (July 23, 2015): 1241–45. http://dx.doi.org/10.3762/bjoc.11.138.

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N-Methylated amides (N,4-dimethylbenzamide and N-methylcyclohexanecarboxamide) were systematically subjected to chemical transformations, namely, N-tosylation followed by nucleophilic substitution. The amide function was converted to the corresponding carboxylic acid, esters, amides, aldehyde, and ketone upon treatment with hydroxide, alkoxide, amine, diisobutylaluminium hydride and Grignard reagent, respectively. In these transformations, N-methyl-N-tosylcarboxamides behave like a Weinreb amide. Similarly, N-methyl-5-phenylisoxazole-3-carboxamide was converted into 3-functionalized isoxazole derivatives. Since the amide was prepared by the cycloaddition reaction of ethynylbenzene and N-methylcarbamoylnitrile oxide, the nitrile oxide served as the equivalent of the nitrile oxides bearing a variety of functional groups such as carboxy, alkoxycarbonyl, carbamoyl, acyl and formyl moieties.

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Li, Feifei, Chunbing Yu, Jian Zhang, and Guofu Zhong. "Weinreb amide directed cross-coupling reaction between electron-deficient alkenes catalyzed by a rhodium catalyst." Organic & Biomolecular Chemistry 15, no. 5 (2017): 1236–44. http://dx.doi.org/10.1039/c7ob00026j.

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A rhodium-catalyzed Weinreb amide directed cross-coupling reaction between electron-deficient alkenes is reported, which provides an efficient route for the synthesis of valuable and versatile Weinreb amide functionalized (Z,E)-butadienes.

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Pace, Vittorio, and Wolfgang Holzer. "Chemoselective Activation Strategies of Amidic Carbonyls towards Nucleophilic Reagents." Australian Journal of Chemistry 66, no. 5 (2013): 507. http://dx.doi.org/10.1071/ch13042.

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Important advancements have been made in recent years in the development of chemoselective additions of nucleophiles to well known inert amide carbonyls in the presence of multi-electrophilic substrates. Herein, we present the most relevant results showing how carbonyl amides can be chemoselectively functionalised in the presence of electrophilic functionalities such as Weinreb amides.

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Rao, Chang, and Chuan-Fa Liu. "Peptide Weinreb amide derivatives as thioester precursors for native chemical ligation." Organic & Biomolecular Chemistry 15, no. 12 (2017): 2491–96. http://dx.doi.org/10.1039/c7ob00103g.

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Thanh Dang, Tuan, Anqi Chen, and Abdul Majeed Seayad. "An Efficient synthesis of Weinreb amides and ketones via palladium nanoparticles on ZIF-8 catalysed carbonylative coupling." RSC Adv. 4, no. 57 (2014): 30019–27. http://dx.doi.org/10.1039/c4ra04614e.

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8

Singh, Jaimala, N. Satyamurthi, and Indrapal Singh Aidhen. "The Growing Synthetic Utility of Weinreb′s Amide." Journal für praktische Chemie 342, no. 4 (2000): 340–47. http://dx.doi.org/10.1002/(sici)1521-3897(200004)342:4<340::aid-prac340>3.0.co;2-1.

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Aidhen, Indrapal, and Sivaraman Balasubramaniam. "The Growing Synthetic Utility of the Weinreb Amide." Synthesis 2008, no. 23 (2008): 3707–38. http://dx.doi.org/10.1055/s-0028-1083226.

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Thode, Christopher J., and Mary Elizabeth Williams. "Grignard Functionalization of Weinreb Amide-Modified Au Nanoparticles." Langmuir 24, no. 12 (2008): 5988–90. http://dx.doi.org/10.1021/la800968c.

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Dissertations / Theses on the topic "Amide de Weinreb"

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Labeeuw, Olivier. "Nouvelles méthodes en synthèse totale : hydrogénation catalytique stéréosélective à l'aide de complexes du ruthénium : application aux synthèses de la sulfobacine A et du (-)-isoavénaciolide." Paris 6, 2004. http://www.theses.fr/2004PA066182.

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Theddu, Naresh. "APPLICATIONS OF ENANTIOPURE SULFINIMINE DERIVED CHIRAL AMINE BUILDING BLOCKS FOR THE ASYMMETRIC SYNTHESIS OF TROPANE ALKALOIDS AND CYCLIC CIS BETA-AMINO ACID DERIVATIVES." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/157444.

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Chemistry
Ph.D.
Chiral amines are ubiquitous in natural products and are found in many drugs and drug candidates. Enantiopure sulfinimines [RS(O)N=CHR1] are useful chiral building blocks for the stereoselective synthesis of amines and amine derivatives. The aim of this thesis research is to develop new methods to access chiral amine building blocks for applications in the synthesis of nitrogen-heterocycles including ring-substituted tropinones, tropanes, cyclic cis-beta-amino acid derivatives, and amino-cyclopentitols.
Temple University--Theses

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Yang, Fanzhi. "Ruthenium(II)- and Copper(I)-Catalyzed C–H Functionalizations." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-8679-C.

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Hisler, Kevin. "New chemistry of weinreb amides and acyl hydrazides." Thesis, University of Strathclyde, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488559.

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This project was concerned with extending the scope of the non-classical Wittig reaction of alkylidenephosphoranes on Weinreb amides discovered previously in Prof. John A. Murphy's group by Aurelien G. J. Commeureuc during his study towards the total synthesis of Muscothiazoles A and B.

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Bowen, Kerisha Andrea. "The Utilization of Sulfinimines (N-Sulfinyl Imines) in the Asymmetric Synthesis of Substituted Pyrrolidines." Diss., Temple University Libraries, 2009. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/33031.

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Chemistry
Ph.D.
The objective of this research was the development of new methods for the asymmetric synthesis of nitrogen containing compounds. As one part of this goal, 3,4-dihydroxyprolines and their derivatives were prepared from sulfinimines (N-sulfinyl imines). During this project new methods were developed for asymmetric hydroxylation and decarboxylation of 3-oxo-2-carboxylate pyrroldines. The application of this new methodology was realized by the total synthesis of the α- and β-glycosidases inhibitor (+)-lentginosine. It was also found that electrophiles regioselectively add to the 4-position of 3-oxo-2-carboxylate-5-substituted pyrrolidines. The addition is accomplished through lithium diisopropyl amide generation of the pyrrolidine dianion. This addition was also compatible with 3-oxo-2-phosophono-5-substituted pyrroldines. Furthermore air oxidation of these pyrrolidines give the corresponding pyrroles. This procedure represents the first general preparation procedure for 2-phonopyrroles, which have been examined as HIV protease inhibitors. A range of β-amino carbonyl compounds were prepared from N-sulfinyl β-amino Weinreb amides in a concise and efficient procedure. A general method for the preparation of a variety of β-amino carbonyl compounds arose from the addition of an assortment of organometallic reagents to the Weinreb amides. The N-sulfinl β-amino Weinreb amides are prepared by reaction of the potassium enolate of N-methoxy-N-methylacetamide with sulfinimines or lithium N,O-dimethylhydroxylamine with N-sulfinyl β-amino esters.
Temple University--Theses

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Schouteeten, Stephanie. "Amides de Weinreb et arènes tricarbonylchrome : synthèse de dérivés 2-benzoylpyridine et 2-benzoylpiperidine." Paris 6, 2005. http://www.theses.fr/2005PA066073.

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Taillier, Catherine. "Préparation d'hétérocyles par métathèse synthèse totale du zoapatanol." Paris 6, 2004. http://www.theses.fr/2004PA066312.

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8

Baker, David Bawden. "Applications of the Heck reaction for the syntheses of substituted pyridines and β,β-disubstituted vinyl Weinreb amides : studies towards the syntheses of inthomycin B and inthomycin C". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:09765f4e-83b9-4bb6-9130-7da3520752e6.

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The Heck reaction has become a fundamental reaction for synthetic organic chemists over the last half century and is utilised heavily in the fine chemical industry and for natural product synthesis. This thesis describes some of the applications of the Heck reaction to modern day organic synthesis. Introduction: This section presents an overview of the Heck reaction starting from its conception during the late 1960s to present day understanding. A variety of ligand classes are described along with commonly accepted catalytic cycles for their activity during the reaction. Results and Discussion: In the first part of the thesis, the use of a cross-metathesis/Heck reaction protocol to synthesise a range of 2,4,6-trisubstituted pyridines is described. Attempts were made to expand the scope of the methodology by employing vinyl Weinreb amides, but this proved unsuccessful for the synthesis of pyridines. Nevertheless, the Heck reaction on vinyl Weinreb amides worked efficiently and the scope of this arylation was explored. Following on, the functionalisation of the Weinreb amide products was studied to generate a range of enone products, some of which would be difficult to synthesise via direct Heck reaction on the respective precursor enone. In the second part of the thesis, previous syntheses of inthomycin B and inthomycin C are described. The synthesis of inthomycin B and inthomycin C were then attempted using an unprecedented Mukaiyama aldol/cross-metathesis based approach to generate the triene core of both natural products.

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Hirner, Sebastian. "New Methodologies in Organic Chemistry: Applications to the Synthesis of α-Amino Acids and Natural Products". Doctoral thesis, KTH, Organisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11112.

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This thesis deals with the development and application of new synthetic methodology in organic chemistry. The first part describes the development of a new protocol for the synthesis of 3-pyrrolines by means of a microwave-assisted ring-expansion reaction of 2-vinylaziridines. In addition, this methodology is implemented as a key-step in a formal total synthesis of the antibiotic (-)-anisomycin. In the second part, a new methodology for the synthesis of arylglycines from Weinreb amides is described. In this procedure, a Grignard reagent is added to the iminium ion formed from the Weinreb amide upon treatment with a base. When a chiral amide is used, the nucleophilic addition proceeds with high diastereoselectivity. Finally, an easy and straightforward synthesis of α-amino amides via a base-mediated rearrangement of modified Weinreb amides into N,O-acetals is presented. Subsequent arylation, alkylation, alkenylation or alkynylation of this intermediate affords the corresponding α-amino amides in excellent yields. Furthermore, a more generalized protocol for the α-arylation of Weinreb amides lacking an α-amino moiety is also discussed.
QC 20100719

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10

Robinson, Stephen Garfield. "The synthesis of oligothiophene functionalized dimethyldihydropyrenes and their electrical and photochromic properties." Thesis, 2008. http://hdl.handle.net/1828/336.

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The synthesis of benzo[e]dimethyldihydropyrene (BDHP) photoswitches with ter-27, quarter-36, and quinque-28 thiophene oligomers attached on the same side of the switch was achieved using Stille coupling reactions. BDHP photoswitches with bi-75, ter-76 and quinque-77 thiophene oligomers attached directly to the switch on one side, and via a carbonyl spacer on the opposite side of the switch were also synthesized. Dimethyldihydropyrene (DHP) photoswitches with a naphthoyl functional group in the 2 position were synthesized using a Friedel Crafts reaction, and ter-96, quinque-97 and septi-98 thiophene oligomers were attached on opposite sides of the switch using Stille coupling reactions. All compounds were characterized by NMR, IR UV-vis spectroscopy and mass spectrometry. The relative rates of the photo-opening reactions under excess light conditions and the UV closing reactions versus BDHP were measured. Improvements in the photo-opening properties of the oligothiophene functionalized switches compared to BDHP were observed. The most dramatic photo-opening improvement was found for the quinquethienyl substituted DHP switch 97 which photo-opened when irradiated with visible light over 100 times faster than BDHP. UV closing rates were virtually the same as that of BDHP. However the addition of oligothiophenes led to an increase in the thermal closing reaction rates. Compounds with the naphthoyl functional group in the 2 position of DHP were found to have dramatically increased thermal closing rates. The electrochemical properties of oligothiophene functionalized BDHP and naphthoyl functionalized DHP switches in the closed form were studied by cyclic voltammetry and spectroelectrochemistry. During the oxidation cycle, a closing reaction from the cyclophanediene (CPD) form to the DHP form of the switches occurred which prevented the study of the electrochemical properties of the switches in the open form. Conductivity testing was performed on the quinquethienyl substituted DHP switch 97 using a gold interdigitated micro electrode array. The conductivity of undoped 97 was greater in the closed DHP isomer than in the open CPD isomer. Irradiation with red or blue light allowed for repetitive switching between the more highly conducting closed form and the less conducting open form. When electrochemically doped, 97 showed improved conductivity over the undoped form but only the conductivity of the closed doped form could be measured due to electrochemically induced closing.

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Book chapters on the topic "Amide de Weinreb"

1

Li, Jie Jack. "Weinreb amide." In Name Reactions. Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-04835-1_301.

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Li, Jie Jack. "Weinreb amide." In Name Reactions. Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-662-05336-2_313.

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3

Shirakawa, S., and K. Maruoka. "Asymmetric Alkylation of a Protected Glycine Weinreb Amide." In Brønsted Base and Acid Catalysts, and Additional Topics. Georg Thieme Verlag KG, 2012. http://dx.doi.org/10.1055/sos-sd-205-00404.

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Taber, Douglass F. "Enantioselective Construction of Alkylated Stereogenic Centers." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0040.

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Xiang-Ping Hu and Zhuo Zheng of the Dalian Institute of Chemical Physics developed (Organic Lett. 2009, 11, 3226; J. Org. Chem. 2009, 74, 9191) a family of Rh catalysts for the enantioselective hydrogenation of allylic phosphonates such as 1. Hon Wai Lam of the University of Edinburgh established (J. Am. Chem. Soc. 2009, 131, 10386) that an alkenyl heterocycle 3 could be reduced with high ee. The product 4 could be hydrolyzed to the carboxylic acid. Ken Tanaka of the Tokyo University of Agriculture and Technology showed (J. Am. Chem. Soc. 2009, 131, 12552) that an isopropenyl amide 6 could be hydroacylated with high ee. Gregory C. Fu of MIT observed (J. Am. Chem. Soc. 2009, 131, 14231) that nitromethane 9 could be added to the allenyl amide 8 to give 10, the product of γ-bond formation. Robert K. Boeckman Jr. of the University of Rochester devised (Organic Lett. 2009, 11, 4544) what appears to be a general protocol for the construction of alkylated ternary and quaternary centers: enantioselective hydroxymethylation of an aldehyde 11. In another approach to the construction of alkylated quaternary centers, Varinder K. Aggarwal of the University of Bristol demonstrated (Angew. Chem. Int. Ed. 2009, 48, 6289) that an enantiomerically enriched trifluoroborate salt 14 could be added to an aromatic aldehyde 15 with retention of absolute configuration. The salt 14 was prepared from the corresponding high ee secondary benzyl alcohol. Weinreb amides are versatile precursors to a variety of functional groups. Stephen G. Davies of the University of Oxford devised (Organic Lett. 2009, 11, 3254) a chiral Weinreb amide equivalent 17 that could be alkylated with high de. The minor diastereomer from the alkylation was readily separable by silica gel chromatography. Keiji Maruoka of Kyoto University established (Angew. Chem. Int. Ed. 2009, 48, 5014) that a chiral phase transfer catalyst was effective for the enantioselective alkylation of the alkynyl ester 19. Emmanuel Riguet of the Université de Reims Champagne-Ardenne developed (Tetrahedron Lett. 2009, 50, 4283) an improved catalyst for the enantioselective addition of malonate 22 to cyclohexenone 21.

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Taber, Douglass F. "C-O Ring Construction: (-)-Sclerophytin A (Morken), (+)-Dictyosphaeric Acid (Taylor), Goniothalesdiol A (Xie/She), (-)-7-Deoxyloganin (Lupton), (-)-Apicularen A (Uenishi), L-783, 277(Banwell) 100." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0052.

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In the course of a synthesis of (-)-sclerophytin A 3, James P. Morken of Boston College showed (J. Am. Chem. Soc. 2010, 132, 16380) that Oshima-Utimoto conditions transformed 1 into 2 with high stereo-and regiocontrol. En route to (+)-dictyosphaeric acid 6, Richard J. K. Taylor of the University of York found (Angew. Chem. Int. Ed. 2010, 49, 5574) that the intramolecular Michael cyclization of 4 proceeded smooothly to give 5. Xingang Xie and Xuegong She of Lanzhou University devised (Synlett 2010, 2283) the In-mediated cyclization of 7 with benzaldehyde, to effect an elegant synthesis of goniothalesdiol A 9. The carbene-mediated cyclization of 10 to 11 developed (Org. Lett. 2010, 12, 4836) by David W. Lupton of Monash University set the stage for the synthesis of (-)-7-deoxyloganin 12. Jun’ichi Uenishi of Kyoto Pharmaceutical University showed (Org. Lett. 2010, 12, 4160) that the Pd-mediated cyclization of 13 proceeded with high diastereocontrol. Intramolecular esterification than led to (-)-apicularen A 15. Martin G. Banwell of the Australian National University established (Heterocycles 2010, 82, 313) that LiHMDS was effective for the cyclization of the alkynyl Weinreb amide 16 to 17. Reduction and deprotection completed the synthesis of the resorcylic lactone L-783, 277 18.

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Harcken, C. "Reduction of Weinreb Amides." In Aldehydes. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-025-00068.

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Taber, Douglass F. "Diels–Alder Cycloaddition: Nicolaioidesin B (Coster), Lycorine (Cho), Bucidirasin A (Nakada), Maoecrystal V (Thomson), Kuwanon J (Wulff/Lei), Vinigrol (Kaliappan)." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0079.

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β-Ocimene 2 is an inexpensive Diels–Alder diene. En route to nicolaioidesin B 4, Mark J. Coster of Griffith University showed (Tetrahedron Lett. 2014, 55, 6864) that the Weinreb amide 1 added to the E isomer of 2 with high selectivity, to give 3. The alkaloid lycorine 8 is found throughout the Amaryllidaceae. Cheon-Gyu Cho of Hanyang University developed (Org. Lett. 2014, 16, 5718) a succinct route to 8 based on the use of the boryl styrene 5 as a Diels–Alder dienophile. Masahisa Nakada of Waseda University (Org. Lett. 2014, 16, 4734) prepared the enantiomerically-pure enone 9 by way of a baker’s yeast reduction of a prochiral diketone. Diels–Alder addition to 10 led to 11, that was carried on to bucidirasin A 12. Regan J. Thomson of Northwestern University prepared (J. Am. Chem. Soc. 2014, 136, 17750) the triene 13 by asymmetric epoxidation of a prochiral enone. Diels–Alder addition of the very reactive nitroethylene to give 14 completed the carbon skeleton of maoecrystal V 15. William D. Wulff of Michigan State University and Xiaoguang Lei of Peking University optimized (Angew. Chem. Int. Ed. 2014, 53, 9257) the organocatalyzed Diels–Alder cycloaddition of 17 to the diene 16. Deprotection then completed the synthesis of the prenylflavonoid kuwanon J 18. In 2012, Barriault described (OHL 20121224) the conversion of 20 to the complex diterpene vinigrol 21. Krishna P. Paliappan of the Indian Institute of Technology Bombay showed (Org. Lett. 2014, 16, 5540) that the triene precursor to 20 could be prepared by ring-closing metathesis of 19. In the absence of ethylene, a different product was formed.

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Ley, S. V., L. G. Milroy, and R. M. Myers. "Double Heteroatom Addition to Weinreb Amides." In Acetals: Hal/X and O/O, S, Se, Te. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-029-00551.

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Taber, Douglass. "The Smith Synthesis of ( + )-Lyconadin A." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0086.

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The pentacyclic alkaloid ( + )-lyconadin A 3, isolated from the club moss Lycopodium complanatum, showed modest in vitro cytotoxicity. A key step in the first reported (J. Am. Chem. Soc. 2007, 129, 4148) total synthesis of 3, by Amos B. Smith III of the University of Pennsylvania, was the cyclization of 1 to 2. The pentacyclic alkaloid (+)-lyconadin A 3, isolated from the club moss Lycopodium complanatum, showed modest in vitro cytotoxicity. A key step in the first reported (J. Am. Chem. Soc. 2007, 129, 4148) total synthesis of 3, by Amos B. Smith III of the University of Pennsylvania, was the cyclization of 1 to 2. The pentacyclic skeleton of 3 was constructed around a central organizing piperidine ring 9. This was prepared from the known (and commercial) enantiomerically-pure lactone 4. The akylated stereogenic center of 9 was assembled by diastereoselective hydroxy methylation of the acyl oxazolidinone 5 with s-trioxane, followed by protection. Reduction of the imide to the alcohol led to the mesylate 7, which on reduction of the azide spontaneously cyclized to give, after protection, the piperidine 8. Selective desilylation of the primary alcohol then enabled the preparation of 9. The plan was to assemble the first carbocyclic ring of 3 by intramolecular aldol condensation of the keto aldehyde 15. The enantiomerically-pure secondary methyl substituent of 15 derived from the commercial monoester 10. Activation as the acid fluoride followed by selective reduction led to the volatile lactone 11. Opening of the lactone with H3CONHCH3HCl gave, after protection, the Weinreb amide 12. Alkylation of the derived hydrazone 13, selectively on the methyl group, led, after deprotection, to 15. The intramolecular aldol condensation of 15 did deliver the unstable cyclohexenone 1. Under the acidic conditions of the aldol condensation, the enol derived from the piperidone added in a Michael sense, from the axial direction on the newly-formed ring, to give the trans-fused bicyclic diketone 2.

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Ley, S. V., L. G. Milroy, and R. M. Myers. "Addition of Nonstabilized Carbanions to Weinreb Amides." In Acetals: Hal/X and O/O, S, Se, Te. Georg Thieme Verlag KG, 2007. http://dx.doi.org/10.1055/sos-sd-029-00550.

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