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Inside Back Cover: Organocatalyzed Domino [3+2] Cycloaddition/Payne‐Type Rearrangement using Carbon Dioxide and Epoxy Alcohols (Angew. Chem. Int. Ed. 35/2018) 下载免费PDF全文
Sergio Sopeña Mariachiara Cozzolino Cristina Maquilón Dr. Eduardo C. Escudero‐Adán Dr. Marta Martínez Belmonte Prof. Dr. Arjan W. Kleij 《Angewandte Chemie (International ed. in English)》2018,57(35):11471-11471
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Rhodium‐Catalyzed [2+2+2] Cycloaddition of Diynes with Carbodiimides and Carbon Dioxide under Ambient Conditions 下载免费PDF全文
Masahiro Ishii Fumiya Mori Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2169-2174
It has been established that a cationic rhodium(I)/H8‐binap complex is able to catalyze the [2+2+2] cycloaddition of diynes with carbodiimides and carbon dioxide under ambient conditions. Enantio‐ and/or regioselective variants of these reactions are also disclosed. 相似文献
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Aniline Dearomatization and Silver‐Catalyzed [3+3] Dipolar Cycloaddition: Efficient Construction of Oxocino[4,3,2‐cd]indoles from 2‐Alkynylanilines and 2‐Alkynylbenzaldoximes 下载免费PDF全文
Dandan Han Prof. Dr. Qiuqin He Prof. Dr. Renhua Fan 《Angewandte Chemie (International ed. in English)》2015,54(47):14013-14016
2‐Alkynylanilines are attractive starting materials in indole synthesis because of their ready availability. Herein, a one‐pot stepwise procedure is reported for efficient construction of multisubstituted oxocino[4,3,2‐cd]indoles from 2‐alkynylanilines and 2‐alkynylbenzaldoximes. The method comprises the oxidative dearomatization of 2‐alkynylanilines, the silver‐catalyzed [3+3] cycloaddition with 2‐alkynylbenzaldoximes, and subsequent thermal radical skeletal rearrangement and aromatization. 相似文献
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Dr. Zhuo Xin Dr. Camille Lescot Dr. Stig D. Friis Prof. Dr. Kim Daasbjerg Prof. Dr. Troels Skrydstrup 《Angewandte Chemie (International ed. in English)》2015,54(23):6862-6866
The first organocatalyzed trapping of CO2 through C? C and C? O bond formation is reported. Alkynyl indoles together with catalytic amounts of an organic base and five equivalents of CO2 resulted in the formation new heterocyclic structures. These tricyclic indole‐containing products were successfully prepared under mild reaction conditions from aromatic, heteroaromatic, and aliphatic alkynyl indoles with complete regioselectivity. Further investigations suggest that C? C bond formation is the initial intermolecular step, followed by lactone‐forming C? O bond formation. 相似文献
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Dr. Fawang Chen Dr. Xiaofang Li Prof. Dr. Bo Wang Dr. Tiegang Xu Dr. Shi‐Lu Chen Dr. Peng Liu Prof. Dr. Changwen Hu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(32):9870-9876
CoII‐substituted α‐Keggin‐type 12‐tungstenphosphate [(n‐ C4H9)4N]4H[PW11Co(H2O)O39]‐ (PW11Co) is synthesized and used as a single‐component, solvent‐free catalyst in the cycloaddition reaction of CO2 and epoxides to form cyclic carbonates. The mechanism of the cycloaddition reaction is investigated using DFT calculations, which provides the first computational study of the catalytic cycle of polyoxometalate‐catalyzed CO2 coupling reactions. The reaction occurs through a single‐electron transfer from the doublet CoII catalyst to the epoxide and forms a doublet CoIII–carbon radical intermediate. Subsequent CO2 addition forms the cyclic carbonate product. The existence of radical intermediates is supported by free‐radical termination experiments. Finally, it is exhilarating to observe that the calculated overall reaction barrier (30.5 kcal mol?1) is in good agreement with the real reaction rate (83 h?1) determined in the present experiments (at 150 °C). 相似文献
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Exploiting the Distal Reactivity of Indolyl Methylenemalononitriles: An Asymmetric Organocatalyzed [4+2] Cycloaddition with Enals Enables the Assembly of Elusive Dihydrocarbazoles 下载免费PDF全文
Dr. Gloria Rassu Dr. Claudio Curti Dr. Vincenzo Zambrano Dr. Luigi Pinna Dr. Nicoletta Brindani Prof. Dr. Giorgio Pelosi Prof. Dr. Franca Zanardi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12637-12640
An unprecedented technique for the in situ generation of indolyl ortho‐quinodimethanes from 2‐methylindole‐based methylenemalononitriles by amine‐mediated remote C(sp3)?H deprotonation was developed. These intermediates were efficiently trapped by diverse enals to provide a rapid entry to 2,9‐dihydro‐1H‐carbazole‐3‐carboxyaldehyde structures through a formal asymmetric [4+2] eliminative cycloaddition governed by a α,α‐diphenylprolinol trimethylsilyl ether catalyst. 相似文献
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Dr. Kalisankar Bera Prof. Dr. Christoph Schneider 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(21):7074-7078
Pyrrolo[1,2‐a]indoles are privileged structural elements of many natural products and pharmaceuticals. An efficient one‐step process for their highly diastereo‐ and enantioselective synthesis, comprising a direct [3+2]‐cycloaddition, has been developed. A chiral BINOL‐derived phosphoric acid catalyzes the reaction of in situ‐generated 2‐methide‐2H‐indoles with 2‐vinylindoles, furnishing the target products incorporating three contiguous stereogenic centers as single diastereoisomers and with excellent yields and enantioselectivities. 相似文献
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Asymmetric Synthesis of Furo[3,4‐b]indoles by Catalytic [3+2] Cycloaddition of Indoles with Epoxides 下载免费PDF全文
Dr. Lili Lin Xiao Yuan Songsong Guo Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15104-15107
A highly efficient N,N′‐dioxide–NiII catalyst system for the catalytic [3+2] cycloaddition of indoles with epoxides through C?C cleavage of oxiranes was accomplished under mild conditions. It provided a promising approach for chiral furo[3,4‐b]indoles in up to 98 % yield with up to 91 % enantiomeric excess (ee) and >95:5 diastereomeric ratio (d.r.). 相似文献
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Konstantin V. Luzyanin Dr. Alexander G. Tskhovrebov M. Fátima C. Guedes da Silva Dr. Matti Haukka Prof. Dr. Armando J. L. Pombeiro Prof. Dr. Vadim Yu. Kukushkin Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(24):5969-5978
[2+3] Cycloadditions! The metal‐mediated [2+3] cycloaddition of acyclic [?O+N(R2)?(H)R3] and nonaromatic cyclic nitrones [?O+Na?CHCH2CH2CbMe2(Na? Cb)] to palladium‐bound isonitriles cis‐[PdCl2(C?NR)2] proceeds under mild conditions to furnish novel heterocyclic carbene complexes, which then undergo N? O bond rupture to give imino complexes and free isocyanates (see scheme).
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Enantioselective Nucleophilic β‐Carbon‐Atom Amination of Enals: Carbene‐Catalyzed Formal [3+2] Reactions 下载免费PDF全文
Xingxing Wu Bin Liu Yuexia Zhang Martin Jeret Honglin Wang Pengcheng Zheng Prof. Song Yang Prof. Bao‐An Song Prof. Dr. Yonggui Robin Chi 《Angewandte Chemie (International ed. in English)》2016,55(40):12280-12284
An enantioselective β‐carbon amination for enals is disclosed. The nitrogen atom from a protected hydrazine with suitable electronic properties readily behaves as a nucleophile. Addition of the nitrogen nucleophile to a catalytically generated N‐heterocyclic‐carbene‐bound α,β‐unsaturated acyl azolium intermediate constructs a new carbon–nitrogen bond asymmetrically. The pyrazolidinone products from our catalytic reactions are common scaffolds in bioactive molecules, and can be easily transformed into useful compounds such as β3‐amino‐acid derivatives. 相似文献
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[3,3]‐Sigmatropic Rearrangement/Allylboration/Cyclization Sequence: Enantioenriched Seven‐Membered‐Ring Carbamates and Ring Contraction to Pyrrolidines 下载免费PDF全文
Dr. Aurélie Macé Dr. Sabrina Touchet Patricia Andres Prof. Fernando Cossío Vincent Dorcet Dr. François Carreaux Dr. Bertrand Carboni 《Angewandte Chemie (International ed. in English)》2016,55(3):1025-1029
The combination of in situ generated α‐isocyanato allylboronic esters and aldehydes afforded seven‐membered‐ring enecarbamates with high levels of diastereo‐ and enantiocontrol. They were easily converted into diversely substituted 1,3‐oxazepan‐2‐ones. An unprecedented rearrangement of 5‐acetoxy‐7‐aryl or styryl derivatives led to tetrasubstituted pyrrolidines. A computational study provides evidence on the feasibility of the proposed mechanism of this unusual ring contraction. 相似文献
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Enguerrand Blondiaux Dr. Jacky Pouessel Dr. Thibault Cantat 《Angewandte Chemie (International ed. in English)》2014,53(45):12186-12190
The first metal‐free catalysts are reported for the methylation of amines with carbon dioxide. Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new methodology enables the methylation of N? H bonds in a wide variety of amines, including secondary amines, with increased chemoselectivity. 相似文献
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Asymmetric Isothiourea‐Catalysed Formal [3+2] Cycloadditions of Ammonium Enolates with Oxaziridines 下载免费PDF全文
Siobhan R. Smith Dr. Charlene Fallan Dr. James E. Taylor Ross McLennan Dr. David S. B. Daniels Dr. Louis C. Morrill Prof. Alexandra M. Z. Slawin Prof. Andrew D. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10530-10536
A highly enantioselective Lewis base‐catalysed formal [3+2] cycloaddition of ammonium enolates and oxaziridines to give stereodefined oxazolidin‐4‐ones in high yield is described. Employing an enantioenriched oxaziridine in this process leads to a matched/mis‐matched effect with the isothiourea catalyst and allowed the synthesis of either syn‐ or anti‐stereodefined oxazolidin‐4‐ones in high d.r., yield and ee. Additionally, the oxazolidin‐4‐one products have been derivatised to afford functionalised enantioenriched building blocks. 相似文献
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[HCo(CO)4]‐Catalyzed Three‐component Cycloaddition of Epoxides,Imines, and Carbon Monoxide: Facile Construction of 1,3‐Oxazinan‐4‐ones 下载免费PDF全文
The three‐component [3+2+1] cycloaddition of epoxides, imines, and carbon monoxide to produce 1,3‐oxazinan‐4‐ones has been developed by using [HCo(CO)4] as the catalyst. The reaction occurs for a wide variety of imines and epoxides, under 60 bar of CO pressure at 50 °C, to produce 1,3‐oxazinan‐4‐ones with different substitution patterns in high yields, and provides an efficient and atom‐economic route to heterocycles from simple and readily available starting materials. A plausible mechanism involves [HCo(CO)4]‐induced ring‐opening of the epoxide, followed by sequential addition of carbon monoxide and the imine, and then ring closure to form the product accompanied by regeneration of [HCo(CO)4]. 相似文献
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PyBidine/Copper Catalyst: Asymmetric exo′‐Selective [3+2] Cycloaddition using Imino Ester and Electrophilic Indole 下载免费PDF全文
Dr. Atsuko Awata Prof. Dr. Takayoshi Arai 《Angewandte Chemie (International ed. in English)》2014,53(39):10462-10465
Electrophilic indoles having two electron‐withdrawing groups undergo nucleophilic attack at C2 and electrophilic functionalization at C3. This is the first enantioselective formal [3+2] cycloaddition using electrophilic indoles. The PyBidine/Cu catalyst smoothly promoted highly enantio‐ and exo′‐selective [3+2] cycloaddition using imino esters and 3‐nitroindoles. This reaction provides a method for the preparation of diverse and complex chiral pyrroloindoline compounds. 相似文献
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Prof. Frédéric‐Georges Fontaine Marc‐André Courtemanche Marc‐André Légaré 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):2990-2996
Metal‐free systems, including frustrated Lewis pairs (FLPs) have been shown to bind CO2. By reducing the Lewis acidity and basicity of the ambiphilic system, it is possible to generate active catalysts for the deoxygenative hydroboration of carbon dioxide to methanol derivatives with conversion rates comparable to those of transition‐metal‐based catalysts. 相似文献
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Lulu Wu Prof. Youming Wang Prof. Haibin Song Prof. Liangfu Tang Prof. Zhenghong Zhou Prof. Chuchi Tang 《化学:亚洲杂志》2013,8(9):2204-2210
An efficient procedure for the stereocontrolled construction of 2H‐thiopyrano[2,3‐b]quinoline scaffolds has been developed, starting from simple compounds. The domino Michael/aldol reactions between 2‐mercaptobenzaldehydes and enals, promoted by chiral diphenylprolinol TMS ether, proceed with excellent chemo‐ and enantioselectivity to give the corresponding synthetically useful and pharmaceutically valuable 2H‐thiopyrano[2,3‐b]quinolines in high yields with 90–99 % ee. 相似文献