Asymmetric synthesis of (2R,5S)-2-methyl-5-hexanolide, the sex pheromone of carpenter bee Xylocopa hirutissima

The stereoselective synthesis of the (2R,5S)-2-methyl-5-hexanolide, a sex pheromone of Xylocopa hirutissima, has been achieved in 6 steps and 33% overall yield. The synthesis relies on an asymmetric N-acetyl thiazolidinethione aldol reaction to establish the C5 stereogenic centers. The remaining stereogenic center at C2 was set through a N-propionylprolinol-mediated asymmetric alkylation reaction. (C) 2008 Elsevier Ltd. All rights reserved.