Scandium-bipyridine-catalyzed, enantioselective alcoholysis of meso-epoxides

The scandium-bipyridine-catalyzed ring-opening of meso-epoxides with aliphatic alcohols has been studied. Aromatic epoxides were ring-opened with >90% ee furnishing valuable 1,2-diol monoethers in typically good yields whereas aliphatic epoxides gave rise to moderate enantioselectivities. The catalyst loading may be lowered to 2-5 mol-% with only marginal effects on yield and enantioselectivity. A strong positive non-linear effect was observed pointing to aggregation phenomena of the chiral catalyst. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).