General and Highly α-Regioselective Zinc-Mediated Prenylation of Aldehydes and Ketones

A simple, efficient, and general alpha-prenylation approach for the synthesis of a variety of alpha-prenylated alcohols has been successfully developed. A wide range of alpha-prenylated alcohol derivatives could be obtained in good yields by highly alpha-regioselective zinc-mediated prenylation of various aldehydes and ketones with prenyl bromide at 120 degrees C in HMPA. By simply altering the reaciton solvent and temperature, the method allows the achievement of a highly notable opposite regiocontrol, providing the expected regiochemical product. The method provides a convenient route for the direct alpha-prenylation of carbonyl compounds in a highly alpha-regioselective manner using a cheap and convenient mediator. Two possible pathways are proposed to account for the formation of these synthetically difficult-to-obtain molecules.