Efficient organocatalyzed solvent-free selective synthesis of conjugated enones

A series of conjugated dienones and enones were synthesized by a reaction of both conjugated and simple aldehydes, respectively, with 1,3-dicarbonyl compounds. and aldehydes Under solvent-free conditions at room temperature in the presence of 10 mol % of L-profine as catalyst. The selective formation of one isomer was, observed exclusively with most of the 1,3-dicarbonyl compounds and aldehydes. The most commonly formed xanthene derivative from the cyclic diketones is inhibited with our protocol, with the exclusive formation of conjugated dienones only. (C) 2008 Elsevier Ltd. All rights reserved.