作者:Ting Ma、Xiao Fu、Choon Wee Kee、Lili Zong、Yuanhang Pan、Kuo-Wei Huang、Choon-Hong Tan
DOI:10.1021/ja1098353
日期:2011.3.9
A new chiral entity, pentanidium, has been shown to be an excellent chiralphase-transfercatalyst. The enantioselective Michaeladdition reactions of tert-butyl glycinate-benzophenone Schiff base with various α,β-unsaturated acceptors provide adducts with high enantioselectivities. A successful gram-scale experiment at a low catalyst loading of 0.05 mol % indicates the potential for practical applications
[EN] NOVEL PHASE TRANSFER CATALYSTS<br/>[FR] NOUVEAUX CATALYSEURS DE TRANSFERT DE PHASE
申请人:UNIV SINGAPORE
公开号:WO2012057709A1
公开(公告)日:2012-05-03
Compounds of formula (I): wherein R1 to R8, and X- are defined herein. Also disclosed are methods of making and using these compounds.
式(I)的化合物:其中R1至R8和X-在此定义。还公开了制备和使用这些化合物的方法。
Optical Resolution of (±)-1,2-Bis(2-methylphenyl)ethylene-1,2-diamine as a Chiral Framework for 2-Iminoimidazolidine with 2-Methylphenyl Pendant and the Guanidine-Catalyzed Asymmetric Michael Reaction of <i>tert</i>-Butyl Diphenyliminoacetate and Ethyl Acrylate
[GRAPHICS](+/-)-1,2-Bis(2-methylphenyl)ethylene-1,2-diamine, prepared from benzil and ammonium acetate, was optically resolved as a chiral framework for 2-(1-benzyl-2-hydroxyethyl)imino-1,3-dimethylimidazolidine with 2-methylphenyl pendants at the 4,5-positions. Catalysis ability of the 1,3-dimethyl-4,5-bis(2-methylphenyl)imidazolidine and the related 1,3-dibenzyl-4,5-diphenylimidazolidine was examined in the asymmetric Michael reaction of t-butyl diphenyliminoacetate and ethyl acrylate.
Preparation of Asymmetric Phase-transfer Catalyst, 1,4-Bis((4S,5S)-1,3-bis(3,5-di-tert-butylbenzyl)-4,5-diphenylimidazolidin-2-ylidene)piperazine-1,4-diium chloride
作者:Esther Cai Xia Ang
DOI:10.15227/orgsyn.097.0274
日期:——
Simple preparation of chiral 1,3-dimethyl-2-iminoimidazolidines (monocyclic guanidines) and applications to asymmetric alkylative esterification
作者:Toshio Isobe、Keiko Fukuda、Tsutomu Ishikawa
DOI:10.1016/s0957-4166(98)00152-9
日期:1998.5
New chiral 1,3-dimethyl-2-iminoimidazolidines (monocyclic guanidines) were simply prepared by the action of primary amines on 2-chloro-1,3-dimethylimidazolinium chlorides, derived from the corresponding urea, in high yields. Modest asymmetric induction in alkylative esterification of benzoic acid with (1-bromoethyl)benzene was observed when the 1,3-dimethyl-4,5-diphenyl-2-[(1-phenyl-or 1-naphthyl)ethylimino]imidazolidines with all S (or R) configurations were used as bases. (C) 1998 Elsevier Science Ltd. All rights reserved.