A practical asymmetric synthesis of homochiral α-arylglycines
摘要:
Enantioselective reduction of a series of substituted aryl trichloromethyl ketones with the CBS-catecholborane reagent afforded homochiral aryl trichloromethyl carbinols which have been elaborated to give homochiral alpha -arylglycines in high e.e. (C) 2001 Elsevier Science Ltd. All rights reserved.
Highly Enantioselective Titanium-Catalyzed Cyanation of Imines at Room Temperature
作者:Abdul Majeed Seayad、Balamurugan Ramalingam、Kazuhiko Yoshinaga、Takushi Nagata、Christina L. L. Chai
DOI:10.1021/ol902540h
日期:2010.1.15
A highly active and enantioselective titanium-catalyzed cyanation of imines at roomtemperature is described. The catalyst used is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-β-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields in 15 min of reaction time using 5 mol % of the catalyst. Various N-protecting groups such as
A Remarkable Titanium-Catalyzed Asymmetric Strecker Reaction using Hydrogen Cyanide at Room Temperature
作者:Balamurugan Ramalingam、Abdul Majeed Seayad、Li Chuanzhao、Marc Garland、Kazuhiko Yoshinaga、Manabu Wadamoto、Takushi Nagata、Christina L. L. Chai
DOI:10.1002/adsc.201000462
日期:2010.9.10
Close to perfect enantioselectivity (up to 98% ee) is obtained for the formation of amino nitriles using hydrogen cyanide (HCN) as the cyanide source at room temperature for the first time. In an operationally simple process, the catalyst generated from a partially hydrolyzed titanium alkoxide (PHTA) and (S)‐N‐salicyl‐β‐amino alcohol ligand, catalyzes the cyanation of imines in a short reaction time