Tandem intramolecular silylformylation-crotylsilylation: highly efficient synthesis of polyketide fragments

Polyketide fragments may be rapidly and efficiently assembled in the tandem intramolecular silylformylation-crotylsilylation of alkenes and alkynes. The reactions establish up to three new stereocenters with good-to-excellent diastereoselectivity, and the use of the reaction in an iterative sense is demonstrated. In addition, a new dihydrosilane alcoholysis reaction has been developed, leading to a highly efficient sequence.