Asymmetric Synthesis of 2-Substituted Dihydrobenzofurans and 3-Hydroxydihydrobenzopyrans through the Enantioselective Epoxidation of O-Silyl-Protected ortho-Allylphenols

The Shi-type epoxidation of O-tert-butyldiphenylsilyl (TBDPS) protected o-allylphenols serves as an efficient strategy to construct the dihydrobenzofurans and dihydrobenzopyrans in up to 97% ee. This methodology led to the enantioselective synthesis of (+)-marmesin, (-)-(3' R)- decursinol, and (+)-lomatin.