作者:Masaru Kondo、Kento Nakamura、Chandu G. Krishnan、Shinobu Takizawa、Tsukasa Abe、Hiroaki Sasai
DOI:10.1021/acscatal.1c00057
日期:2021.2.5
have been developed to control the catalytic activity by photoirradiation. Azobenzene binaphthyl crown ether (ABCE) can switch its reactivity and selectivity through structural transformation of the crown ether moiety induced by E/Z photoisomerization of azobenzene. (Z)-ABCE promoted enantioselective alkylation of the glycine Schiff base to afford chiral amino acidderivatives in good yields with high
Enantioselective reactions of tert-butyl glycinate–benzophenone Schiff base catalyzed by chiral phase-transfer catalyst in aqueous media without any organic solvent
phase-transfer catalyzed enantioselective alkylations of tert-butyl glycinate–benzophenone Schiff base were investigated in aqueousmedia without any organic solvent. Reactions in aqueousmedia smoothly proceeded to give the desired product in higher yield than under standard liquid–liquid biphasic conditions. In aqueousmedia the formation of benzophenone, which was caused by in situ hydrolysis of Schiff
A convenient method for asymmetric alkylation of glycine imine esters using solid supports
作者:Haitao Yu、Hideko Koshima
DOI:10.1016/j.tetlet.2003.10.023
日期:2003.12
A symmetric alkylation of butyl glycinate-benzophenone Schiff base proceeded smoothly on clays and alumina at room temperature to afford alkylated products in high yields and good enantioselectivities. (C) 2003 Elsevier Ltd. All rights reserved.
Asymmetric alkylation of glycine imine esters using solid supports preloaded with base
作者:Haitao Yu、Setsuko Takigawa、Hideko Koshima
DOI:10.1016/j.tet.2004.07.002
日期:2004.9
Investigations into the use of solid supports preloaded with base for the asymmetric alkylation of a benzophenone-derived glycine-imine was described. Residual traces of water on the support dramatically accelerated the reactions to complete within a few minutes. The conditions employed in the present synthesis are mild, efficient and general. (C) 2004 Elsevier Ltd. All rights reserved.
Synthesis of new dimeric-PEG-supported cinchona ammonium salts as chiral phase transfer catalysts for the alkylation of Schiff bases with water as the solvent
作者:Xin Wang、Liang Yin、Ting Yang、Yongmei Wang
DOI:10.1016/j.tetasy.2006.12.024
日期:2007.1
The water-soluble PEG-supported cinchona ammonium salts were successfully synthesized and used as chiral phase transfer catalysts for the asymmetric alkylation of tert-butyl benzophenone Schiff base derivatives with high chemical yields (up to 98%) and enantio selectivities (up to 97%) in aqueous media. The recycling results showed that the polymers were stable and rarely lost activities. (c) 2007 Elsevier Ltd. All rights reserved.