Ozonolytic Cleavage of 3-Oxidopyrilium Betaine-Derived Cycloadducts: Simple and Efficient Access to Stereodefined Tetrahydrofurans

A range of bicyclic allylic alcohols, obtained from the highly stereoselective reduction of endo-adducts derived from [3+2] cycloaddition of 3-oxidopyrilium betaine to various olefins, undergo efficient ozonolytic cleavage followed by reduction to yield stereodefined tetrahydrofurans in high overall yields as single diastereoisomers.