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1
Wu, Hao. "Catalytic Enantioselective Formations of C–B, C–C and C–Si Bonds by Organic Molecules or Transition-Metal Complexes." Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104759.
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Thesis advisor: Amir H. Hoveyda<br>Catalytic enantioselective reactions are of great importance in synthetic organic chemistry. Thus, development of efficient, selective and easily accessible catalyst for various bond formations is the main task in our laboratories. First, we have developed the first broadly applicable enantioselective boryl conjugate addition reactions to a variety of α,β-unsaturated carbonyls, promoted by a chiral Lewis basic N-heterocyclic carbene. The valuable β-boryl carbonyls were further used in complex molecule syntheses. The mechanism of these C–B bond formations was studied in details. We have also developed a practical method for enantioselective addition of an allene unit to aryl-, heteroaryl- and alkyl-substituted Boc-aldimines. These efficient C–C bond formations, catalyzed by an aminophenol-derived boron-based catalyst, were further utilized in succinct syntheses of anisomycin and epi-cytoxazone. Finally, chiral NHC–Cu complexes were employed for site-, diastereo- and enantioselective silyl conjugate additions to acyclic and cyclic dienones and dienoates. The precious enantiomerically enriched allylsilane obtained can be converted into a ketone-aldol type product, which is difficult to access through alternative methods<br>Thesis (PhD) — Boston College, 2015<br>Submitted to: Boston College. Graduate School of Arts and Sciences<br>Discipline: Chemistry
2
Richter, Frank. "Development of the Solution-Spray Flash-Vacuum-Pyrolysis Technique in the Synthesis of Allenyl Isothiocyanates and Synthesis of Complex 2-Amino-1,3-thiazole Derivatives." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-175339.
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Gas-phase thermolysis is a long-known and well established method for the preparation of reactive species. It is, however, limited to relatively volatile substances, which are easily vaporised. In the present work, the solution-spray technique for preparative scale was developed. With this technique, it is possible to subject low-volatile substances, which hardly vaporise even under high-vacuum conditions, to gas-phase thermolysis. By utilising oil nozzles used in heating and burner systems, it was possible to integrate a stable solution-spray into the existing flash-vacuum-pyrolysis system. The influence of several variables, such as flow-rate, pressure, temperature and solvent was determined. The solution-spray technique was applied in [3,3]-sigmatropic rearrangements of certain propargyl thiocyanates to the corresponding allenyl isothiocyanates. Furthermore, the parent compound propa-1,2-dienyl isothiocyanate was reacted with various sterically demanding primary and secondary amines to form 2-amino-1,3-thiazoles in moderate to excellent yields. Based on this, a catalyst-free four-center three-component reaction was developed. 2-Amino-1,3-thiazoles with complex substituents in 5-position at the heterocyclic ring are formed. Reaction mechanisms are discussed to explain the occurance of a highly substituted 1,3-thiazine structure. The influence of reaction temperature, concentrations and solvent were determined and are also discussed. It was shown that 2-amino-5-methyl-1,3-thiazoles are the apparently first aromatic substance class, that readily undergoes Prins-type 1,3-dioxane ring-formation<br>Die Gasphasenthermolyse ist eine lang bekannte und etablierte Methodik zur Synthese reaktiver Spezies. Sie ist allerdings auf flüchtige Substanzen mit einer guten Verdampfbarkeit beschränkt. Für schwerflüchtige Verbindungen, welche sich selbst im Hochvakuum nur mäßig oder gar nicht in die Gasphase bringen lassen, wurde in der vorliegenden Arbeit die Solution-Spray-Technik für die Anwendung im präparativen Maßstab entwickelt. Unter Verwendung von Ölzerstäuberdüsen, wie sie in der Heizungs- und Brennertechnik Anwendung finden, wurde die Erzeugung eines stabilen Lösungs-Sprays in die vorhandene Blitzvakuumpyrolyse-Technik integriert. Der Einfluss verschiedener Variablen, wie Flussrate, Druck, Temperatur und Lösungsmittel wurde untersucht. Die Solution-Spray-Technik wurde für die [3,3]-sigmatrope Umlagerung bestimmter Propargylthiocyanate zu Allenyl-isothiocyanaten angewendet. Des Weiteren wurde Propa-1,2-dienylisothiocyanat – das einfachste Allenylisothiocyanat – mit diversen sterisch anspruchsvollen primären und sekundären Aminen in mäßigen bis exzellenten Ausbeuten zu 2-Amino-1,3-thiazolen umgesetzt. Darauf aufbauend konnte eine Vier-Zentren-drei-Komponenten-Reaktion entwickelt werden. Es entstehen in hohen Ausbeuten 2-Amino-1,3-thiazole mit komplexen Substituenten an der 5-Position des Heterocyclus. Reaktionsmechanismen werden diskutiert um die alternative Bildung einer hochsubstituierten 1,3-Thiazinstruktur zu erklären. Der Einfluss von Reaktionstemperatur, Konzentration und Lösungsmittel auf das Produktverhältnis wurde ebenfalls untersucht und wird diskutiert. Es konnte gezeigt werden, dass 2-Amino-5-methyl-1,3-thiazole als offenbar erste aromatische Substanzklasse sehr gute Substrate für die Bildung von 1,3-Dioxanen nach Prins darstellen
3
Cooper, Lisa. "Synthesis of multi-heteroaromatic compounds by platinum-catalysed nucleophilic addition to allenes." Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/66858/.
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This thesis describes the extensive investigation into the platinum-catalysed double addition of nucleophiles to allenes and in particular, our efforts towards the synthesis of 2,3’-bis-indolyl methanes (BIMs), which are important compounds with potential biologically important properties. The first chapter will describe the background of both inter- and intramolecular addition reactions to allenes with a range of different nucleophiles and array of metal catalysts. The latter part of this chapter will focus on the two synthetic strategies for BIM formation, firstly, the classical approach involving the Friedel-Crafts reaction between indoles and carbonyl compounds using protic or Lewis acid catalysis and secondly, the more recent methods involving the use of transition metal catalysis for the addition of indoles to π-bonds such as alkynes, allenes and cyclopropene via direct double hydroarylation. The first part of the results and discussion chapter describes the attempts to expand the scope of the inter-intermolecular addition reaction of heteroatom and heteroaromatic nucleophiles to a model allene, generating a range of bis-substituted products. Despite an extensive investigation of both nucleophiles (e.g. imidazole, pyrazole, thiophenol and aniline) and the reaction conditions (e.g. incorporation of silver salts for chloride abstraction and gold catalysis), we could not extend the method efficiently enough for the formation of these compounds. Therefore, the second part of this chapter focuses on the successful intra-intermolecular platinum-catalysed addition reaction of an external indole to an indolyl allene with subsequent formation of 6-endo cycles, 2,3’-BIMs or tris- and allylic derivatives. (Diagram – cannot be copied over) This section describes the optimisation of the reaction conditions to favour the formation of the desired 2,3’-BIM, an investigation to determine the effect that substituents on either the indolyl allene or the external indole has on the overall formation of the 2,3’-BIM and the 6-endo cycles, and a detailed mechanistic investigation to determine the overall mechanism of the reaction. A trend was found with EDG favouring the formation of the desired 2,3’-BIM and the EWG favouring the formation of the 6-endo cycles or the tris- and allylic derivatives. The mechanistic investigation revealed that the 6-endo cycles are intermediates in the formation of the 2,3’-BIM, with a platinum carbene complex as the key intermediate between the three products.
4
Liu, Zi [Verfasser], and Bernhard [Akademischer Betreuer] Breit. "Rhodium-catalyzed addition of alcohols and N-hydroxy imides to allenes and alkynes." Freiburg : Universität, 2017. http://d-nb.info/1153335298/34.
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Wang, Yu-Hsuan [Verfasser]. "Enantioselective Rhodium-Catalyzed Addition of Imines and Oximes to Allenes / Yu-Hsuan Wang." München : Verlag Dr. Hut, 2018. http://d-nb.info/1174426101/34.
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Beck, Thorsten M. [Verfasser]. "Rhodium-catalyzed atom economic addition of enolizable 1,3-dicarbonyl compounds to allenes and alkynes / Thorsten M. Beck." München : Verlag Dr. Hut, 2017. http://d-nb.info/1135597006/34.
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Spreider, Pierre [Verfasser]. "Übergangsmetall-Katalysierte Atomökonomische Intramolekulare Additionen von Pronukleophilen an Allene und deren Anwendung in Totalsynthesen / Pierre Spreider." München : Verlag Dr. Hut, 2018. http://d-nb.info/1174426187/34.
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Spreider, Pierre A. [Verfasser]. "Übergangsmetall-Katalysierte Atomökonomische Intramolekulare Additionen von Pronukleophilen an Allene und deren Anwendung in Totalsynthesen / Pierre Spreider." München : Verlag Dr. Hut, 2018. http://d-nb.info/1174426187/34.
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Scharf, Ingolf. "Synthesen und Reaktionen akzeptorsubstituierter Diallene." Doctoral thesis, [S.l. : s.n.], 2009. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200900168.
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Arnaout, Abdulkarim al. "Synthese regioselective de dihydropyridines et de pyridines 2- ou 4-fonctionnalisees : applications." Poitiers, 1987. http://www.theses.fr/1987POIT2254.
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Hsu, Ray-Hsi, and 許瑞熙. "The Nucleophilic Addition Reactions of Allenyl Complexes of Iridium(III)." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/43637175919116355799.
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碩士<br>國立臺灣大學<br>化學學系<br>81<br>Vaska 錯合物與溴丙炔進行氧化加成反應得到穩定的 (.sigma.-丙二烯
基)銥錯合物,在低溫下以三氟甲烷硫酸基銀作用,可將溴離子拔除,得到三
氟甲烷硫酸基配位的丙二烯基銥錯合物,與水或醇類反應,可進行親核加成
反應,成功地合成了 .eta.3-2-羥基烯丙基 以及.eta.3-2-烷氧基烯丙基
錯合物,由其 X-ray 單晶繞射,知其結構為雙三角椎,一氧化碳及氯離子分
別位在軸向反位,並探討其在室溫下之分解反應。若以.eta.3-2-烷氧基烯
丙基錯合物為起始物,在室溫下與有機胺反應,結果得到.eta.3-氮代三亞
甲基甲烷銥錯合物(7a,7b,7c),7a 與 7b 分別有 X-ray 單晶繞射結構。
根據 7a 和 7b 之晶體結構,比較其中金屬至中心碳的鍵長以及中心碳至
氮之鍵長後知: 若中心碳至氮之鍵長愈短,則金屬至中心碳的鍵長愈長。
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Hsu, Ray-Hsi, and 許瑞熙. "The Nucleophilic Addition Reactions of h1-Allenyl and h3-Propargyl Complexes of Platinum(II)." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/36189348332863667765.
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博士<br>國立臺灣大學<br>化學系研究所<br>85<br>(h1-丙二烯基)鉑錯合物1，Pt(h1-CH=C=CH2)(Br)(PPh3)2，經AgBF4脫溴後，以二氯甲烷
當溶劑可得(h3-炔丙基)鉑錯合物2，[Pt(h3-CH2CCH)(PPh3)2](BF4)；若以乙氰為溶劑的
情形下，乙氰可配位到此空位，形成乙氰配位的(h1-丙二烯基)鉑錯合物3，[Pt(h1-CH=C=
CH2)(CH3CN))(PPh3)2](BF4)。(h1-丙二烯基)鉑錯合物1與碳陰離子Na[CH(X)(Y)]混合，
溶劑則用乙氰/二氯甲烷之混合溶劑，可得產物為(h3-三亞甲基甲烷) 鉑錯合物，Pt[h3-C
H2C(CXY)CH2](PPh3)2(X = Y = COMe，4a；X = COMe，Y = CO2Me，4b；CXY = C(CO)(CH2
)3(CO)，4c；X = COPh，Y = SO2Ph，4d； X = COPh，Y = CN，4e；X = Y = CO2Me，4f
；X = Y = SO2Ph，4g；X = SO2Ph，Y = CN，4h) ；錯合物4a-4d的溶液經加熱後可得有
機物5a-5d，然而錯合物5e溶液經加熱後卻得到一金屬代六員環錯合物6，此錯合物並有X-
光單晶繞射結構。(h3-炔丙基)鉑錯合物2在室溫下與Na[CH(CN)2]反應，亦得到產物為乙
氰配位的(h1-丙二烯基)鉑錯合物3與碳陰離子反應後，碳陰離子可取代乙氰配位在金屬上
，產物為Pt(h1-HC=C=CH2)[CH(X)(Y)](PPh3)2，可能分別以碳(錯合物7、8)、氧(錯合物9
)、氮(錯合物10)配位至金屬上，經加熱後，則具有單一選擇性，皆與丙二烯基的中心碳
形成新的碳-碳鍵，得到產物為(h3-三亞甲基甲烷)鉑錯合物，或直接得到環化的有機物。
錯合物10若與甲基乙烯基酮反應，則經Michael addition進行親核加成反應，產物為Pt(h
1-HC=C=CH2)(PPh3)2[NCC(CH2CH2COCH3)COPh)]，錯合物11。利用各種不同強度的酸將錯
合物4質子化，可得[h3-(b-取代)烯丙基]鉑錯合物{Pt[h3-CH2C(CHXY)CH2](PPh3)2}(BF4)
(X = Y = CN，12a；X = Y = CO2Me，12b；X = Y = SO2Ph，12c；X = CN，Y = SO2Ph，1
2d)，並知鹼性強弱順序為4f > 4g > 4h > 4i。加入鹼如NEt3，即可從錯合物12回復為錯
合物4。錯合物2與20當量的含拉電子基甲烷CHE2R在-15oC下反應亦可得產物為[h3-(b-取
代)烯丙基]鉑錯合物{Pt[h3-CH2C(CE2R)CH2](PPh3)2}(BF4)(E = COMe, R = H, 13a; E =
CO2Et, R = Me, 13b) ， CE2R也加成到(h3-炔丙基)的中心碳上。若與1,3-環己二酮反
應則得到[h3-(b-烷氧基)(h3-炔丙基)鉑錯合物2跟indole、3-Methylindole、4-pyridone
反應，可進行類似親電性取代反應，產物為[h3-(b-取代)烯丙基]鉑錯合物15、16、17；
若與推電子基取代的苯衍生物反應，可得產物為[h3-(b-苯環取代)烯丙基]鉑錯合物，{Pt
[h3-CH2C(Aryl)CH2](PPh3)2}(BF4)(R1 = NMe2， R2 = R3 = H， 18a；R1 = R2 = R3 =
OMe， 18b；R1 = R2 = R3 = OiPr， 18c；R1 = R2 = OMe，R3 = H， 18d； R1 = R2 =
R3 = OH，18e；R1 = NMe2， R2 = OH，R3 = H，18f) 。錯合物18a、18b與不同的親核劑
作用可經還原脫去得到苯乙烯的衍生物，錯合物18f以鹼作用後，氧原子攻擊利用(h1-丙
二烯基)鉑錯合物3與多羥基醇反應可在丙二烯基的中心碳上形成碳-氧鍵，產物為[h3-(b-
烷氧基取代)烯丙基]鉑錯合物，但此反應須加熱方能進行。
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Chiang, Wen-Chih, та 江文智. "Investigation of Addition Reaction of Platinum (II) η3- Propargyl/Allenyl Complex with Inorganic Acids". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/17619331583790013486.
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碩士<br>國立臺灣大學<br>化學系<br>86<br>There has been increasing interest in developing the synthesis
of the central-carbon-substituted h3-allyl complexes
viaregioselective nucleophilic addition of a h3-propargyl
complex.Herein, we introduce the reactions of a h3-propargyl
complex of platinum with dihydrogenphosphate or hydrogensulfate,
which yield the first b-substituted phosphato- or sulfato-allyl
complexes. When 2 eq. of [(Ph3P)2Pt(h3-C3H3)] (1)and 1 eq. of
[CH3(CH2)4NH2PO4] were allowed to react,a diallyl phosphate [(
Ph3P)2Pt(h3-(CH2)2C(O))]2PO2(BF4)(4) complex was formed.
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Tsai, Fu-Yu, та 蔡福裕. "The Synthesis of Chalcogenolatoallyl Species via Carbon- Chalcogen Bond Forming in η3-Allenyl/Propargyl Complexes and Reaction Mechanism of Nucleophilic Addition to the Metal- Allenyl Complexes". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/34907255052231918350.
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陳玉昆. "Mechanistic Study of Nucleophilic Addition of Amine to Octahedral Iridium η1-Allenyl Leading to η3-Azatrimethylenemethane Derivatives". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/14031800758949910908.
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碩士<br>國立臺灣大學<br>化學學系<br>83<br>Oxidative-addition of propargyl halides to the Vaska complex yielded neutral octahedral allenyl complexes Ir(η1-CH=C=CH2)(CO)(Cl)2(PPh3)2 1a , Ir(η1-CH=C=CH2)(CO)(Br)(Cl)(PPh3)2 1b, Ir(ηCH=C=CH2)(CO)(Br)(Cl)(PPh3)2 1c. Treatment of 1b with AgOTf resulted Ir(η1-CH=C=CH2)(CO)(Cl)(PPh3)2(OTf) 2 in good yields. The reaction of 2 with ammonia or primary amines led to substltutlon yielding,｛Ir(η1-CH=C=CH2)(CO)(Cl)(PPh3)2(NH2R)}(OTf)(5a R=H, 5b R=Me, 5c R=Et,5d R=iPr, 5e R=PhCH2). Benzenesulfoamide didn't react with 2, however, the reaction of comples 2 and sodium benzenesulfoamide led to a neutral product Ir(η1-CH=C=CH2)(CO)(Cl)(PPh3)2(NHSO2Ph)7 which undergo protonation to form the ionic amine derivatives {Ir(η1-CH=C=CH2)(CO)(Cl)(PPh3)2(NH2SO2Ph)｝(CH3COO)8。 Intriguingly, aniline and its derlvatlves reacted with complex 2 to form the (η3-azatrlmethylenemethane) related species Ir(η3-CH2C(NHC6H5X)-CH2)(CO)(Cl)(PPh3)2(OTf) 9 (9a R=H, 9b R=OMe, 9c R=Me, 9d R=F, 9e R=NO2)(HN-TMM) and Ir(η3-CH2C(NRPh)CH2)(CO)(Cl)(PPh3)2(OTf) 10 (10a R=Me, 10b R=Ph). Mechanistic studies suggested that such reactlons first form aniline-substituted lonic complexes which further led to the NTMM-Irldium products. Relevant mechanistic results will be revealed.
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Cheng, Yuan-Chung, та 鄭原忠. "(Mechanistic Investigation of nucleophilic Addition of Amine and Water to Platinum(II) η^3-Propargyl/Allenyl Complex - A Density Functional Study". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/99991586259283696309.
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Boller, Timothy Marlow. "Regioselectivity of nucleophilic addition to n³-propargyl complexes and electronic effects on a novel equilibrium between n³-allenyl complexes of rhenium." 2002. http://www.library.wisc.edu/databases/connect/dissertations.html.
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Chang, Hao-Ming, and 張浩銘. "Palladium-Catalyzed Addition Reactions of Allenes." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/20626266639712840363.
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博士<br>國立清華大學<br>化學系<br>89<br>Several new palladium-catalyzed addition reactions of allenes and their applications in organic synthesis are described. This thesis consists of two parts. The first part is concerned with new methodology to generate 1,3-butadiene derivatives and the three-component coupling reactions of nucleophilic substitution of p-allylpalladium complexes. The second part deals with the studies on the carbonyl allylation via apparent charge reversal of p-allylpalladium intermediate.
In the first part, a palladium-catalyzed reaction based on carbopalladation of allenes to generate a p-allylpalladium intermediate followed by deportonation of the resulting p-allylpalladium species was carried out to transfer allenes into substituted 1,3-butadienes. In addition to the synthesis of 1,3-butadienes, the p-allylpalladium species reacted with carboxylate and azide anions leading to the formation of allylic carboxylates and allylic azides, respectively.
In the second part, highly regio- and stereoselective allylation of aldehydes by allenes proceeds smoothly in aqueous/organic media in the presence of PdCl2(PPh3)2, HCl(aq), and SnCl2. The reaction occurs via hydrostannylation of allenes and allylation of aldehydes by the in situ generated allyltrichlorotins to afford the homoallylic alcohols. In addition, the allylation of carbonyl compounds by allylic alcohols via the formation and the apparent charge reversal of the p-allylpalladium complex in the catalytic system, 5 mol % PdCl2(PPh3)2, 10 mol % SnCl2, and excess Zn as metal reducing agent, gave the corresponding homoallylic alcohols.
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Kuo-Jui, Chang, and 張國瑞. "Palladium-Catalyzed Addition of Allenes and Its Application and Cobalt-Catalyzed Regioselective Carbocyclization." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/51478289629268352647.
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博士<br>國立清華大學<br>化學系<br>92<br>A highly regio and stereoselective method for the synthesis of various 2-silylallylboronates from allenes and silaborane catalyzed by palladium complexes and initiated by organic iodides is described. A variety of monosubstituted aryl and alkylallenes RCH=C=CH2 and 1,1-dimethylallene react with silaborane in the presence of Pd(dba)2 (5 mol %) and an organic iodide 3 (2-methyl-3-iodo-2-cyclohexen-1-one) (10 mol%) in EA at 80 oC to give the corresponding silaboration products in moderate to excellent yields. The product formation can be explained based on an unusual and new mechanistic pathway involving a three-component assembling reaction. This catalytic silaboration is totally regioselective with the silyl group of silaborane adding to the central carbon and the boryl group to the unsubstituted terminal carbon of allene. Furthermore, the reactions show very high stereoselectivity giving the corresponding E isomer as the major species.
And this silaboration chemistry can be applied to the synthesis of homoallylic alcohols. Treatment of allenes with silaborane and aldehydes in the presence of Pd(dba)2 (5 mol%) and alkenyl iodide 3 (10 mol%) at 80 °C in ethyl acetate for 5 h afforded homoallylic acohols in good yields with excellent syn selectivity.
An efficient cobalt-catalyzed carbocylization for the synthesis of indenols is described. 2-Iodophenylketones and 2-iodophenylaldehydes undergo carbocyclization with various disubstituted alkynes in the presence of CoI2(dppe), and zinc powder in acetonitrile at 80 oC for 3 h to afford the corresponding indenol derivatives in good to excellent yields. For some unsymmetrical alkynes, the carbocyclization was remarkably regioselective affording a single regioisomer. A possible mechanism for this cobalt-catalyzed carbocyclization reaction is proposed.
The cobalt-catalyzed carbocyclization reaction is successfully extended to the synthesis of indenes and a new method for reductive decyanation. Thus, the reaction of 2-iodophenylketones and 2-iodophenylaldehydes with acrylates H2C=CHCO2R proceeds smoothly in the presence of CoCl2(dppe) /dppe, and zinc powder in acetonitrile at 80 oC for 24 h to afford the corresponding indenes in moderate to good yields. Interestingly, when acrylonitrile H2C=CHCN was employed for the carbocylization, reductive decyanation also occurred to give indene derivatives without the cyano functionality. A possible mechanism for this cobalt-catalyzed carbocyclization reaction is also proposed.
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Wang, Shu-Huei, and 王淑惠. "Synthesis of Pyrazoles and Isoxazoles from Allenyl Ketones and A New Additional Reaction for Synthesis of b-Halo Ketones." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/85930026189372885183.
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博士<br>淡江大學<br>化學學系博士班<br>93<br>Part I:
Pyrazole and Isoxazole are well-known as useful synthetic intermediates
and important structural units which are widely observed in natural
products and biological active molecules. Several methods for synthesis
of isoxazoles have been developed and reported and the cyclocondensation
reaction of b-diketone with hydroxylamine is one of the most common used
method. The limitation of this method is the unsymmetrical b-dicarbonyl
compounds can not be prepared regioselectively. The condensation reactions
of oxime dianions with esters provide a regioselective accesses to generate
b-keto oximes, which then undergo cyclodehydrations to afford isoxazoles.
We wish to report a new synthetic method which improves and permits a variety
of substituted pyrazoles and isoxazoles are easily prepared. Pyrazoles were
synthesized from a reaction mixture of hydrazine dihydrochloride, sodium
methylate and allenyl ketone in anhydrous N, N-dimethylformamide at room
temperature. Isoxazoles were synthesized from a reaction mixture of hydroxylamine
hydrochloride, cesium carbonate and allenyl ketone in anhydrous dimethyl
sulfoxide at room temperature.
Part II:
b-Halo carbonyl compounds are potentially biologically active molecules
and important synthetic intermediates in organic synthesis. Recently, our
laboratory reported a simple and an effective method for synthesis of
a,b-unsaturated ketone which is an useful synthetic precursor for
preparation of a,b-unsaturated ketone. A reaction mixture of a,b-unsaturated
ketone, boron trichloride and ethylene glycol in dichloromethane was stirred
at 0oC and b-chloro ketone was produced in high yield. The b-bromo ketone
was obtained as the major product when a reaction mixture of a,b-unsaturated
ketone , boron tribromide and ethylene glycol in dichloromethane was stirred
at 0oC after 0.5h.
21
Green, Eleanor Virginia. "Nutrient addition and crop yield of an alley cropping system in the piedmont of Georgia." 2002. http://purl.galileo.usg.edu/uga%5Fetd/green%5Feleanor%5Fv%5F200205%5Fms.
Full text
22
Gao, Bing-Fong, and 高秉豐. "Organocascade Synthesis of Annulated (Z)-2-Methylene Pyrans: Nucleophilic Conjugate Addition of Hydroxy Coumarins toBranched Nitroenynes via Allene Formation/Oxa-Michael Cyclization/Alkene Isomerization Sequence." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/5w38m9.
Full textAbstract:
碩士<br>國立臺灣師範大學<br>化學系<br>104<br>Enantioselective organocatalysis has contributed significantly to asymmetric synthesis by delivering highly functionalized complex structural entities with multiple stereogenic centers in high optical purity. Most of enyne system in previous literature was studied to establish by using synergistic/sequential metal catalysis, but it was the few on organic asymmetric cascade reaction. The organocascade reaction was established between 1,3-nitro enynes and 4-hydroxy coumarin to afford pyrano-annulated scaffolds in high yields (up to 88% yield) and excellent stereoselectivities (up to >20:1 Z:E and >99% ee) under bifunctional quinine derived squaramide and DABCO catalysis. The reaction proceeded through sequential conjugate addition, allene formation, intramolecular oxa-Michael 6-endo-dig cyclization and DABCO catalyzed olefin isomerization.
23
Scharf, Ingolf. "Synthesen und Reaktionen akzeptorsubstituierter Diallene." Doctoral thesis, 2008. https://monarch.qucosa.de/id/qucosa%3A19064.
Full textAbstract:
In der vorliegenden Arbeit wird die Darstellung neuer terminaler, akzeptorsubstituierter 1,2,4,5-Hexatetraene sowie eines Heptatetraens beschrieben.
Des weiteren wird die nucleophile Addition von formal Stickstoffwasserstoffsäure an in situ erzeugten Alleneinheiten unter Bildung von sonst nur schwer zugänglichen 1,4-Diazido-1,3-butadienen dokumentiert. Auf analoge Weise gelingt es ebenfalls, neuartige 1,4-Diazido-2,3-dihalogen-1,3-butadiene zu synthetisieren.
Es wird gezeigt, dass die Umsetzung von primären Aminen mit akzeptorsubstituierten 1,2,4,5-Hexatetraenen unter doppelter nucleophiler Addition zu Pyrrolen verläuft. Durch die Umsetzung mit Dimethylmalonat gelingt dadurch die Synthese eines Cyclopentadiens.
Die Reaktion eines Diallenylsulfons mit primären Aminen liefert analog verschiedene neue Sechsringheterocyclen. Diese zeigen interessante dynamische Effekte, welche durch die 1H-NMR-Tieftemperatur- sowie 1H-NMR-Hochtemperatur-Spektroskopie dokumentiert werden.
Die Umsetzung von Hexa-2,4-diin-1,6-diolen mit Sulfenylchloriden liefert durch doppelte [2,3]-sigmatrope Sulfenat-Sulfoxid-Umlagerung 1,2,4,5-Hexatetraene. Diese zeigen zum Teil spontane, doppelte [2,3]-sigmatrope Sulfoxid-Sulfenat-Umlagerungen, welche in der Literatur bislang falsch interpretiert wurden. Die Molekülstruktur der gebildeten Sulfenate wird durch eine Einkristall-Röntgenstrukturanalyse beispielhaft belegt.
In einigen Fällen kann eine weitere, zweifache Sulfenat-Sulfanylketon-Umlagerung beobachtet werden. Die Molekülstruktur der sechsfach umgelagerten Produkte kann wiederum durch die Einkristall-Röntgenstrukturanalyse eines Vertreters dieser Verbindungsklasse bestätigt werden.
Durch die Verwendung von Alkylsulfenylchloriden, welche zum Teil auf neuartige, einfache Weise erhalten werden, gelingt die Synthese der Sechsfachumlagerungsprodukte mit fast quantitativen Ausbeuten.
24
Cérat, Pascal. "Synthèse et utilisation de dérivés de cyclopropane-1,1-diesters énantioenrichis vers l'obtention d'allènes hautement substitués." Thèse, 2011. http://hdl.handle.net/1866/6296.
Full textAbstract:
Le présent mémoire a pour sujet le développement d’une méthode rapide et efficace vers la production d’allènes hautement substitués à partir de dérivés cyclopropaniques électrophiles énantioenrichis. L’avancement de méthodes synthétiques intéressantes pour la production asymétrique de ces dérivés de cyclopropane-1,1-diesters sera également présenté.
Dans un premier temps, les différentes méthodes de synthèses des cyclopropanes activés seront abordées, ainsi que leur utilisation dans la préparation de molécules plus complexes. Par la suite, les techniques précédentes de préparation asymétrique des allènes seront introduites, démontrant ainsi la difficulté de leur accessibilité. Le développement d’une méthode fiable pour la synthèse de cyclopropane-1,1-diesters utilisant les ylures d’iodonium sera présenté. Finalement, l’accessibilité à plusieurs types d’allènes hautement substitués par l’utilisation de cuprates sera détaillée.
Dans une seconde partie, il sera davantage question de l’accessibilité des cyclopropane-1,1-diesters énantioenrichis. Ces derniers sont d’un intérêt particulier, car ils constituent le point de départ de notre méthodologie précédente. Le développement d’une méthode pouvant être utilisée à grande échelle et à faible coût a donc été explorée. Les deux derniers chapitres présenteront donc les tentatives de générer ces cyclopropanes activés par résolution cinétique ou encore par l’hydrogénation asymétrique des cyclopropènes correspondants.<br>The subject of this present M.Sc. thesis is the developpement of an efficient and fast methodology toward the production of highly substituted allenes using enantioenriched cyclopropanes derivatives. The development of new synthetic methodologies in the production of these enantioenriched cyclopropan-1,1-diesters will be presented.
First, the various methodologies for the preparation of activated cyclopropanes will be discussed along with their uses in the synthesis of more complex molecules. Then, the precedents in the field of asymmetric allenes synthesis will be introduced. The developpement of a viable method for the synthesis of cyclopropane-1,1-diesters using iodonium ylides will be presented. Finally, the accessibility of different highly substituted allenes by the used of cuprates will be detailed.
In a second part, we will elaborate on the accessibility of the enantioenriched cyclopropane-1,1-diesters derivatives. These compounds are interesting, because they are used as starting materials in the previous methodology of allenes synthesis. This methodology has to be usable in large scale and at small cost. The last two chapters of this thesis will present the alternatives strategies for the preparation of these activated cyclopropanes by either kinetic resolution or the asymmetric hydrogenation of cyclopropenes.