Direct asymmetric allylic alkylation of butenolides with Morita-Baylis-Hillman carbonates.

ABSTRACT

The direct asymmetric allylic alkylation of beta,gamma-butenolides with MBH carbonates to access gamma,gamma-disubstituted butenolides containing adjacent quaternary and tertiary chiral centers has been presented in excellent stereoselectivities (86-96% ee, dr >955) and moderate to good yield (50-83%). Their synthetic utility has been well demonstrated by the facile construction of bicyclic lactones bearing 4-5 stereogenic centers.