Highly enantioselective aryl transfer to aldehydes: a remarkable effect of sulfur substitution in amino thioacetate ligands

Org Lett. 2008 Mar 20;10(6):1235-7. doi: 10.1021/ol8001249. Epub 2008 Feb 21.

Abstract

Chiral amino thioacetate ligands were prepared from the corresponding amino alcohols and used as catalysts for enantioselective aryl transfer reaction. The amino thioacetates were remarkably superior to the corresponding amino alcohols. Low catalyst loadings of only 1-2.5 mol % were sufficient to achieve excellent enantioselectivity as well as high conversion in short reaction time. The results reveal that the thioacetoxy moiety of the amino thioacetates has a surprisingly beneficial effect in enhancing the asymmetric induction.