Investigation of a stereoselective co-mediated rearrangement reaction.
A stereocontrolled approach to alpha-alkyl beta-alkynyl cyclohexanones is reported through a Lewis acid mediated rearrangement reaction of enol ethers bearing an Co-alkyne moiety. The reaction proceeds with high levels of stereoselectivity in the presence of Ti- and B-Lewis acids to provide a range of alpha,beta-disubstituted cyclohexanones in high yield although the products are prone to epimerization at the alpha-position in the presence of the B-promoter system. The potential for an enantioselective variant of this process is outlined, and a rationale for the observed stereochemical trends and detailed structural analyses of the ketone products are described.
Carbery
David R
DR
Department of Chemistry, University of Sheffield, Brook Hill, UK.
Reignier
Serge
S
Miller
Neil D
ND
Adams
Harry
H
Harrity
Joseph P A
JP