Enantioselective total syntheses of novel PKC activator (+)-decursin and its derivatives using catalytic asymmetric epoxidation of an enone

The catalytic asymmetric total syntheses of (+)-decursin and three related natural products, (+)-decursinol, (−)-prantschimgin and (+)-marmesin, were achieved for the first time using catalytic asymmetric epoxidation of an enone as the key step. The catalytic asymmetric epoxidation of enone was found to be promoted effectively by novel multifunctional asymmetric catalyst generated from La(O-i-Pr)3, BINOL and OAsPh3 in a 1:1:1 ratio to afford epoxide in 94% yield and 96% ee, which was recrystallized to give the optically pure epoxide.