S-(+)-5-(PHENYLTHIO)-2-PENTANOL AND S-(+)-4-(PHENYLTHIO)-2-BUTANOL - READILY PREPARED, USEFUL ADDITIONS TO THE CHIRALITY POOL - HIGHLY ENANTIOSELECTIVE SYNTHESES OF NATURALLY-OCCURRING SPIROKETAL PHEROMONES

The new chirons (S)-4-(phenylthio)-2-butanol (4) and (S)-5-(phenylthio)-2-pentanol (3) have been prepared efficiently in high enantiomeric excess by enzymatic reduction of the corresponding readily available ketones. Using the latter as a chiral building block, the highly optically enriched insect pheromonal components (5S,7S)-7-methyl-1,6-dioxaspiro[4.5]decane (7), (2S,6R)-2-methyl-1,7-dioxaspiro[5.5]undecane (8), and (2S,6R)-2-methyl-1,7-dioxaspiro[5.6]dodecane (9) have been synthesized in one pot by sequential deprotonation, reductive lithiation, transmetalation with cerium(III) chloride, treatment with lactones, and acidification.