共查询到20条相似文献,搜索用时 9 毫秒
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Prof. Dr. Scott E. Denmark Dr. Tyler W. Wilson 《Angewandte Chemie (International ed. in English)》2012,51(40):9980-9992
This Minireview provides an overview on the development of silyl ketene imines and their recent applications in catalytic, enantioselective reactions. The unique structure of the ketene imine allows a diverse range of reactivity patterns and provides solutions to existing challenges in the enantioselective construction of quaternary stereogenic carbon centers and cross‐benzoin adducts. A variety of reactions for which silyl ketene imines have been applied are presented with an overall goal of inspiring new uses for these underutilized nucleophiles. 相似文献
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Inspired by nature, the use of helical biopolymer catalysts has emerged over the last years as a new approach to asymmetric catalysis. In this Concept article the various approaches and designs and their application in asymmetric catalysis will be discussed. 相似文献
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《Angewandte Chemie (International ed. in English)》2017,56(39):11700-11733
Non‐racemic chiral boronic esters are recognised as immensely valuable building blocks in modern organic synthesis. Their stereospecific transformation into a variety of functional groups—from amines and halides to arenes and alkynes—along with their air and moisture stability, has established them as an important target for asymmetric synthesis. Efforts towards the stereoselective synthesis of secondary and tertiary alkyl boronic esters have spanned over five decades and are underpinned by a wealth of reactivity platforms, drawing on the unique and varied reactivity of boron. This Review summarizes strategies for the asymmetric synthesis of alkyl boronic esters, from the seminal hydroboration methods of H. C. Brown to the current state of the art. 相似文献
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Electrophilic cyclizations of unactivated alkenes play highly important roles in the synthesis of useful building blocks. This account describes our contributions to the rational design of monofunctionalized chiral Lewis base catalysts for enantioselective iodo‐ and protocyclizations. For the stereoselective promotion of electrophilic bromocyclizations, nucleophilic phosphite–urea cooperative catalysts have been designed. 相似文献
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Prof. Dr. Barry M. Trost Dr. Christopher A. Kalnmals 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(9):1906-1921
Metal-catalyzed allylic alkylation reactions between dual nucleophiles and dual electrophiles represent a powerful set of methods for the synthesis of small-, medium-, and even large-sized rings. Using this strategy, a handful of simple allylic diol derivatives can be transformed into a broad array of complex carbo- and heterocycles of varying ring sizes in just a single step. Because of their ability to rapidly generate complexity, annulative allylic alkylation reactions between dual nucleophiles and dual electrophiles have been extensively employed in the total synthesis of both natural products and pharmaceutical compounds. 相似文献
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Asymmetric Conjugate Additions and Allylic Alkylations Using Nucleophiles Generated by Hydro‐ or Carbometallation 下载免费PDF全文
Dr. Rebecca M. Maksymowicz Andrew J. Bissette Dr. Stephen P. Fletcher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5668-5678
This Minireview discusses catalytic asymmetric conjugate addition and allylic alkylation reactions where the nucleophiles were generated in situ by hydrometallation or carbometallation. This exciting recent trend in asymmetric catalysis promises to expand the range of transformations available for the rapid and selective assembly of complex, functional molecules for both academic and industrial research. This Minireview aims to serve as a reference for studies reported to date and discusses the current state‐of‐the‐art, scope and limitations of these processes. 相似文献
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Direct Difluoromethylation of Alcohols with an Electrophilic Difluoromethylated Sulfonium Ylide 下载免费PDF全文
Jiansheng Zhu Yafei Liu Prof. Dr. Qilong Shen 《Angewandte Chemie (International ed. in English)》2016,55(31):9050-9054
A general method for the formation of alkyl difluoromethylethers under mild reaction conditions and with good functional‐group tolerance was developed. The development of the method was based on the invention of a stable, electrophilic, difluoromethylating reagent, difluoromethyl‐(4‐nitrophenyl)‐bis(carbomethoxy) methylide sulfonium ylide, which was synthesized by reaction of the easily available 4‐nitrophenyl (difluoromethyl)thioether and dimethyl diazomalonate in the presence of a rhodium catalyst. 相似文献
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Xingfeng Bai Caizhi Wu Shaozhong Ge Yixin Lu 《Angewandte Chemie (International ed. in English)》2020,59(7):2764-2768
An asymmetric palladium and copper co‐catalyzed Heck/Sonogashira reaction between o‐iodoacrylanilides and terminal alkynes to synthesize chiral oxindoles was developed. In particular, a wide range of CF3‐substituted o‐iodoacrylanilides reacted with terminal alkynes, affording the corresponding chiral oxindoles containing trifluoromethylated quaternary stereogenic centers in high yields with excellent enantioselectivities (94–98 % ee). This asymmetric Heck/Sonogashira reaction provides a general approach to access oxindole derivatives containing quaternary stereogenic centers including CF3‐substituted ones. 相似文献
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Enantioselective H-Bond-Directing Approach for Trienamine-mediated Reactions in Asymmetric Synthesis
L Albrecht F Cruz Acosta A Fraile A Albrecht J Christensen KA Jørgensen 《Angewandte Chemie (International ed. in English)》2012,51(36):9088-9092
Right direction: The presented enantioselective strategy for the preparation of diversely functionalized tetrahydroxanthones is based on a trienamine-mediated cycloaddition between 2,4-dieneals and activated chromones. It is possibile to control the stereochemical outcome of such reactions by employing an H-bond-directing aminocatalyst. 相似文献
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Radical Cyclization/ipso‐1,4‐Aryl Migration Cascade: Asymmetric Synthesis of 3,3‐Difluoro‐2‐propanoylbicyclo[3.3.0]octanes 下载免费PDF全文
Watcharaporn Thaharn Dr. Darunee Soorukram Dr. Chutima Kuhakarn Dr. Patoomratana Tuchinda Prof. Dr. Vichai Reutrakul Prof. Dr. Manat Pohmakotr 《Angewandte Chemie (International ed. in English)》2014,53(8):2212-2215
A novel method for the asymmetric synthesis of 3,3‐difluoro‐2‐propanoylbicyclo‐[3.3.0]octanes involves an unprecedented intramolecular radical cyclization/ipso‐1,4‐aryl migration cascade. 相似文献