Diastereoselective Addition of Organocerium(III) Reagents Derived from 3-Substituted Propargyl Bromides to Aldehydes

Abstract

Various cerium allenyl reagents were generated by transmetallation of allenyl Grignard compounds with CeCl3 and sub­sequent conversion into homopropargylic alcohols by addition to various aliphatic and aromatic aldehydes. The α-acetylenic alcohols were obtained with regioselectivities and diastereoselectivities up to 98% de in favor of the threo-diastereomers.