Enantio- and diastereoselective assembly of tetrahydrofuran and tetrahydropyran skeletons with all-carbon-substituted quaternary stereocenters.

Chiral phosphoric acids (HB*) catalyze the asymmetric desymmetrization of meso 1,3-diols through mono-transacetalization with a tethered acetal unit. This new strategy leads to the efficient assembly of tetrahydrofuran and tetrahydropyran skeletons bearing remote all-carbon-substituted quaternary stereocenters that are not straightforward to access by other methods.