Synthesis and characteristic odour of optically active 3‐hydroxy‐4‐phenyl‐2‐butanone

Abstract

ABSTRACTEnantioselective syntheses of two stereoisomers of 3‐hydroxy‐4‐phenyl‐2‐butanone were investigated via Shi's asymmetric epoxidation or Sharpless asymmetric dihydroxylation of silyl enol ether. (R)‐3‐Hydroxy‐4‐phenyl‐2‐butanone was obtained in 73% enantiomeric excess (ee) by Shi's catalyst/oxone and 80% ee by AD‐mix‐β, while the (S)‐isomer was prepared in 62% ee by AD‐mix‐α. The characteristic odour of the optically active products was analysed by gas chromatography–olfactometry. The (R)‐isomer had a relatively weak fruity and green odour, while the (S)‐isomer had a strong caramel, sweet and floral aroma. Additionally, the (S)‐isomer presented a stronger odour intensity than did the (R)‐isomer. Copyright © 2011 John Wiley & Sons, Ltd.