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
A New Class of Acetophenone-based Cinchona Alkaloids as Phase-transfer Catalysts: Application to the Enantioselective Synthesis of α-Amino Acids
作者:Jian Lv、Liping Zhang、Lei Liu、Yongmei Wang
DOI:10.1246/cl.2007.1354
日期:2007.11.5
A new class of acetophenone-based cinchona alkaloid-derived quaternary ammonium salts were prepared and evaluated as phase-transfercatalysts in the enantioselective alkylation of glycine imine est...
Merrifield resin supported cinchona ammonium salts bearing 2'-fluorobenzene, 2'-cyanobenzene and 2'-N-oxypyridine groups were prepared and applied to the phase-transfer catalytic alkylation of N-(diphenylmethylene)glycine tert-butyl ester for the enantioselective synthesis of alpha-amino acids (76-96% ee). (c) 2008 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.
Synthesis of Both Enantiomers of Chiral Phenylalanine Derivatives Catalyzed by Cinchona Alkaloid Quaternary Ammonium Salts as Asymmetric Phase Transfer Catalysts
作者:Lei Jin、Shuai Zhao、Xin Chen
DOI:10.3390/molecules23061421
日期:——
A practical synthesis of both enantiomers of unnatural phenylalanine derivatives by using two pseudoenantiomeric phase transfercatalysts is described. Through asymmetric α-alkylation of glycine Schiff base with substituted benzyl bromides and 1-(bromomethyl)naphthalene under the catalysis of O-allyl-N-(9-anthracenmethyl) cinchoninium bromide (1f) and O-allyl-N-(9-anthracenylmethyl)cinchonidium bromide