A Convenient Method for Synthesis of Optically Active Methylphenidate from N-Methoxycarbonylpiperidine by Utilizing Electrochemical Oxidation and Evans Aldol-type Reaction
摘要:
A new method to prepare optically active methylphenidate starting from piperidine is described. The method consists of a transformation of N-methoxycarbonylated piperidine to the corresponding alpha-methoxylated carbamate utilizing electrochemical oxidation followed by the coupling reaction with optically active Evans imides to produce optically active methylphenidate derivatives with high stereoselectivity (erythrolthreo=5.3/94.7, the three isomer; 99.6%ee). (C) 2000 Elsevier Science Ltd. All rights reserved.
Direct asymmetric α-chlorination of aryl aceticacidderivatives was achieved with a novel trinary activation system consisting of a catalytic amount of NiCl2/(R)-BINAP, Et3SiOTf, and a tertiary amine base. The reaction smoothly afforded the chlorinated compound in good yield with up to 89 % ee. Application of this reaction to a less acidic crotonic acidderivative gave the β,γ-unsaturated α-chlorinated
Enantioselective α-Arylation of <i>N</i>-Acyloxazolidinones with Copper(II)-bisoxazoline Catalysts and Diaryliodonium Salts
作者:Aurélien Bigot、Alice E. Williamson、Matthew J. Gaunt
DOI:10.1021/ja206047h
日期:2011.9.7
A new strategy for the catalytic enantioselective α-arylation of N-acyloxazolidinones with chiral copper(II)-bisoxazoline complexes and diaryliodoniumsalts is described. The mild catalytic conditions are operationally simple, produce valuable synthetic building blocks in excellent yields and enantioselectivities, and can be applied to the synthesis of important nonsteroidal anti-inflammatory agents
[formula: see text] This report describes a new method to prepare optically active methylphenidate starting from piperidine. The method consists of a transformation of N-methoxycarbonylpiperidine to the corresponding alpha-methoxylated carbamate I by utilizingelectrochemicaloxidation followed by the coupling reaction with optically active Evans imides II to produce optically active methylphenidate
[公式:见正文]该报告介绍了一种从哌啶开始制备旋光哌醋甲酯的新方法。该方法包括通过利用电化学氧化将N-甲氧基羰基哌啶转化为相应的α-甲氧基化氨基甲酸酯I,然后与旋光的Evans酰亚胺II偶联反应,以生产具有高立体选择性苏氨酸-(2R,2可以通过三步轻松地从III制备R'-哌醋甲酯(IV; Ar = Ph;利他林)。