Enantio- and Diastereoselective Organocatalytic α-Alkylation of Aldehydes with 3-Substituted 2-(Bromomethyl)acrylates

The catalytic direct alpha-alkylation of aldehydes with 2-(bromomethyl)acrylates has been accomplished, giving rise to alpha-branched and functionalized aldehydes of high diastereo- and enantiopurity. The influence of the nature of the ester group of the acrylates in reaction stereoselectivity and especially in reactivity is investigated. Optimum conditions implicate the use of phenyl acrylates in conjunction with organocatalyst 8. Application of thus obtained adducts in synthesis is illustrated with a concise stereocontrolled preparation of trisubstituted cyclopentenes.