Chiral α-Methyl-homoallylic Alcohols from Yeast-Generated Precursors. Synthesis of (4R,5S) Sitophilure

Optically active (3S,4R)-3,4-dihydroxy-4-methyl-6-phenyl-hex-5-ene and (2S,3RS)-2,3-dihydroxy-3-methyl-5-phenyl-pent-4-ene, previously obtained from fermenting baker’s yeast reduction of the corresponding Ketones, are transformed either into optically active α-ethyl and α-methyl ketones, or into α-methyl homoallylic alcohols from which enantiomerically pure (4S,5R) sitophilure, (2S,3R)-2-methyl-1,3-butandiol and its (2S,3S)-diastereoisomer have been prepared.