Ligand-Assisted Rate Acceleration in Transacylation by a Yttrium - Salen Complex. Demonstration of a Conceptually New Strategy for Metal-Catalyzed Kinetic Resolution of Alcohols

(matrix presented) Yttrium-salen complexes effect transacylation between enolesters and chiral secondary alcohols, resulting in varying degrees of kinetic resolution. Even though the enantioselectivity remains modest (k_fast/k_slow up to 4.81), these results represent the first demonstration of a conceptually new metal-catalyzed acyl transfer process that results in kinetic resolution. On the basis of the solid-state structure of the catalyst, a novel associative mechanistic pathway is proposed for the reaction.