VO(acac)2/TBHP catalyzed epoxidation of 2-(2-alkenyl)phenols. Highly regio and diastereoselective oxidative cyclization to 2,3-dihydrobenzofuranols and 3-chromanols

The VO(acac)(2)/TBHP (1.5 mol%/1.3 equiv) system has been successfully used for the epoxidation of variously double bond substituted 2-(2-alkenyl)phenols under mild conditions. Moreover, a one-pot conversion to 2,3-dihydrobenzofuranols and 3-chromanols is achieved with high or complete regio- and diastereoselectivity in the presence of catalytic amounts of TFA (20 mol%). This metal-catalyzed methodology was shown to be more practical and superior to the previously employed m-CPBA for the epoxidation and the oxidative cyclization of 2-(2-alkenyl)phenols