Enantioselective Synthesis of (−)-Curcumanolide A Using Enzymatic Transesterification of meso-Spirodiol

meso -Spirodiol 12 and spirodiacetate 13 were stereoselectively prepared using π-face selective Grignard addition to norbornanone 7 . Asymmetric transesterification of meso -diol and hydrolysis of meso -diacetate were studied using lipases. Pseudomonas fluorescen s lipase-catalyzed transesterification of meso -diol 12 afforded the monoacetate (−)- 21 of high enantiomeric excess (>99% ee). The formal synthesis of (−)-curcumanolide A has been achieved from the optically active (−)- 21 .