In the presence of catalytic amounts of PtCl2 and AgOTf, 5-methyl-5-hexen-1-ol reacted with aldehydes to give 2,3-disubstituted tetrahydropyrans in moderate to high yields with trans-stereoselectivity. Use of 5-methyl-5-hexen-1-ols bearing a methyl group at the C1-, C2-, or C3-position led to highly stereoselective synthesis of trisubstituted tetrahydropyrans.