Diastereo- and enantioselective iridium-catalyzed carbonyl propargylation from the alcohol or aldehyde oxidation level: 1,3-enynes as allenylmetal equivalents

Abstract

Axial to axial to point chirality transfer: Exposure of conjugated enynes to alcohols in the presence of an iridium catalyst modified by a segphos ligand results in the generation of aldehyde-allenyliridium pairs and formation of enantiomerically enriched products of carbonyl anti-(α-methyl) propargylation (see scheme). An identical set of products are obtained from aldehydes under related transfer hydrogenation conditions by employing formic acid as a reductant. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.