Synthesis of Longhorn Beetle Pheromone Components by Proline-Mediated α-Hydroxylation of Alkyl Ketones

Abstract

AbstractThe stereoselective synthesis of several components of the aggregation pheromones of numerous longhorn beetle species is described. These attractants consist of 3-hydroxy-2-alkanones and 2,3-alkyldiols­ with chain lengths varying from six to ten carbons. The 3R- and 3S-series are generated by organocatalytic α-hydroxylation of alkyl ketones with nitrosobenzene in the presence of l- or d-proline, respectively, to obtain the hydroxyketones in high enantiomeric excess. Further reduction and chromatographic separation lead to the enantiomerically pure diols that complete the library.