Construction of Contiguous Tetrasubstituted Chiral Carbon Stereocenters via Direct Catalytic Asymmetric Aldol Reaction of α-Isothiocyanato Esters with Ketones
contiguous tetrasubstituted chiral carbon stereocenters via directcatalyticasymmetric aldol reaction of alpha-substituted alpha-isothiocyanato esters with unactivated simple ketones is described. A Bu(2)Mg/Schiff base catalyst promoted the aldol addition/cyclization sequence at room temperature, giving protected alpha-amino-beta-hydroxy esters with contiguous tetrasubstituted chiral carbon stereocenters
Construction of contiguous tetrasubstituted chiral carbon stereocenters via direct catalytic asymmetric aldol and mannich-type reactions
作者:Shigeki Matsunaga、Tatsuhiko Yoshino
DOI:10.1002/tcr.201100020
日期:2011.9.29
Catalytic asymmetricsynthesis of unnatural amino acids with vicinal tetrasubstituted chiral carbon stereocenters is described. In the first part, direct catalytic asymmetricaldolreaction of simple non‐activated ketone electrophiles with α‐substituted α‐isothiocyanato ester donors was realized. A Mg/Schiff base catalyst promoted the aldolreaction, and α‐amino‐β‐hydroxy esters were obtained in up