Pyrrolidine-Mediated Direct Preparation Of (E)-Monoarylidene Derivatives Of Homo- And Heterocyclic Ketones With Various Aldehydes

An efficient method for the facile synthesis of (E)-monoarylidene derivatives of homo-and heterocyclic ketones with various aldehydes in the presence of a pyrrolidine organocatalyst has been achieved. A range of alpha,beta-unsaturated ketones were obtained in moderate to high yields (up to 99%). Unlike the Claisen-Schmidt condensation process, the formation of undesired bisarylidene byproducts is not observed. The possible reaction mechanism suggests that the reaction proceeds via a Mannich-elimination sequence.