Efficient and stereocontrolled synthesis of polysubstituted tetrahydropyrans by an allylstannylation/Bi(III)-promoted cyclisation strategy

A novel sequence, involving the condensation between a highly functionalised allylstannane and various aldehydes, followed by a bismuth triflate-promoted intramolecular Sakurai cyclisation (IMSC) of the resulting homoallylic alcohols, allows a rapid and stereocontrolled access to a range of polysubstituted tetrahydropyrans. (C) 2001 Elsevier Science Ltd. All rights reserved.