Asymmetric and diastereoselective Mannich reactions using hydantoin as a chiral auxiliary
摘要:
The Mannich reaction of titanium enolates of a chiral hydantoin with various aldimines smoothly occurred in good yields and with high anti-diastereoselectivity. The Mannich adducts can be readily cleaved by alcoholysis to afford several beta-amino ester derivatives in good yields and in almost enantiomerically pure form. (C) 2012 Elsevier Ltd. All rights reserved.
作者:Paweł Dydio、Christophe Rubay、Tendai Gadzikwa、Martin Lutz、Joost N. H. Reek
DOI:10.1021/ja208589c
日期:2011.11.2
We report an achiral bisphosphine rhodiumcomplex equipped with a binding site for the recognition of chiral anion guests. Upon binding small chiral guests--cofactors--the rhodiumcomplex becomes chiral and can thus be used for asymmetric catalysis. Screening of a library of cofactors revealed that the best cofactors lead to hydrogenation catalysts that form the products with high enantioselectivity
Synthesis of Novel Chiral Cholic Acid-Based Molecular Tweezers Containing Unsymmetrically Disubstituted Urea Units Using Microwave Irradiation
作者:Bitao Zeng、Zhigang Zhao、Lijun Zhou、Qinghan Li
DOI:10.3184/174751912x13318994425202
日期:2012.4
An efficient procedure has been developed for the synthesis of new chiral cholic acid molecular tweezer artificial receptors by linking an unsymmetrically disubstituted urea to methyl deoxycholate via a carbonate chain using microwave irradiation. The structures of these new receptors were confirmed by 1H NMR, IR, MS spectra and elemental analysis. Their binding properties were examined by UV-Vis spectra
Asymmetric and diastereoselective Mannich reactions using hydantoin as a chiral auxiliary
作者:Xuan-Ran Li、Cui-Fen Lu、Zu-Xing Chen、Yan Li、Gui-Chun Yang
DOI:10.1016/j.tetasy.2012.09.006
日期:2012.10
The Mannich reaction of titanium enolates of a chiral hydantoin with various aldimines smoothly occurred in good yields and with high anti-diastereoselectivity. The Mannich adducts can be readily cleaved by alcoholysis to afford several beta-amino ester derivatives in good yields and in almost enantiomerically pure form. (C) 2012 Elsevier Ltd. All rights reserved.