Reactive resin facilitated preparation of an enantiopure fluorobicycloketone
作者:Audrey Wong、Christopher J. Welch、Jeffrey T. Kuethe、Enrique Vazquez、Mohamed Shaimi、Derek Henderson、Ian W. Davies、David L. Hughes
DOI:10.1039/b312180c
日期:——
A facile preparation of enantiopure ethyl (1S,5S,6S)-6-fluoro-2-oxobicyclo[3.1.0]hexane-6-carboxylate is described. The key feature of the synthesis involves copper-catalyzed enantioselective intramolecular cyclopropanation of a diazoketone to form endo-fluorocyclopropane in a single operation. Removal of a problematic chloroketone impurity using a reactive resin treatment enabled a high throughput
Concise Enantioselective Synthesis of Oxygenated Steroids via Sequential Copper(II)-Catalyzed Michael Addition/Intramolecular Aldol Cyclization Reactions
作者:Nathan R. Cichowicz、Will Kaplan、Yaroslav Khomutnyk、Bijay Bhattarai、Zhankui Sun、Pavel Nagorny
DOI:10.1021/jacs.5b08528
日期:2015.11.18
functionalized oxygenated steroids is described. This strategy is based on chiral bis(oxazoline) copper(II) complex-catalyzed enantioselective and diastereoselective Michael reactions of cyclic ketoesters and enones to install vicinal quaternary and tertiary stereocenters. In addition, the utility of copper(II) salts as highly active catalysts for the Michael reactions of traditionally unreactive β,β'-enones
Enantioselective construction of vicinal tetrasubstituted carbon stereocenters is a formidable challenge in organic synthesis. A copper-catalyzed asymmetric decarboxylative propargylic substitution with 3-amino oxindoles as trisubstituted carbon nucleophiles and propargylic cyclic carbonates as tertiary carbon electrophiles was developed. A range of 3-amino-3,3′-disubstituted oxindoles bearing vicinal quaternary-tetrasubstituted
邻位四取代碳立体中心的对映选择性构建是有机合成中的一项艰巨挑战。开发了一种铜催化的不对称脱羧炔丙基取代,其中 3-氨基羟吲哚作为三取代碳亲核试剂,炔丙基环状碳酸酯作为叔碳亲电试剂。以高产率和良好的立体选择性(高达 98% 的产率,>20:1 dr 和 98.5:1.5 er)获得了一系列带有连位季四取代碳立体中心的 3-氨基-3,3'-二取代羟吲哚.