[(BINAP)Re(O)Cl-3] as an efficient catalyst for olefination of chiral alpha-substituted aliphatic aldehydes

A convenient one-pot preparation of [(BINAP) Re(O)Cl-3] (6) is described. This complex was demonstrated to be an efficient catalyst for the olefination of aldehydes by reaction with alpha-diazo esters, with essentially quantitative yields and up to 98:2 geometric selectivity. The potential for using enantiopure [(BINAP)Re(O)Cl-3] (6) to promote an asymmetric kinetic resolution of racemic alpha-stereogenic aldehydes was investigated, but no enantiotopic discrimination was observed. Control experiments indicate that this lack of selectivity stems from the in-situ formation of a phosphonium ylide, which accounts for product formation in a non-metal associated reaction pathway. (C) 2010 Elsevier B. V. All rights reserved.