Organocatalytic Michael addition of aldehydes to a β-silylmethylene malonate to form intermediates for the enantioselective synthesis of hydroxylated valerolactones and piperidines

摘要

The direct Michael addition of enolizable aldehydes to dimethyl(phenyl) silylmethylene malonate was catalysed by an (S)-diphenylprolinol trimethylsilyl ether/acetic acid combination. The adducts were formed in good yield, high diastereoselectivity and excellent enantioselectivity. Chiral valerolactone and piperidine skeletons embedded with a silyl and other functionalities have been made out of the adducts. A total synthesis (+)-simplactone B has been achieved from one of the adducts.