Diastereoselective Construction of [alpha]-Silyltetrahydropyranols through Silyl-Oxa-Prins Cyclization

The Brønsted acid mediated selective silyl-oxa-Prins cyclization of [alpha]-silyloxy homoallylsilanes with various aldehydes was achieved. Synthetically valuable [alpha]-silyltetrahydropyranol products were obtained in high yields with excellent diastereoselectivities. Both syn- and anti-isomeric tetrahydropyranols were selectively obtained by tuning the olefinic geometry of the substrates. The procedure is operationally simple and convenient to perform even on a large scale under mild conditions.