Metal‐free stereoselective synthesis of tetrahydropyrans bearing adjacent quaternary and tertiary stereocenters by acid mediated cyclization

A convenient route for the preparation of tetrahydropyran (THP) derivatives with a quaternary and tertiary vicinal stereocenters is reported. The atom economy acid‐catalyzed cyclization of allylsilyl alcohols provided polysubstituted tetrahydropyrans in good yields and excellent diastereoselectivities (>95:5). In comparison with the traditional oxymercuration procedure, this approach resulted to be more efficient in both yield and stereocontrol.