Journal of the American Chemical Society, Vol.130, No.8, 2422-2423, 2008
Enantioselective Diels-Alder reaction of simple alpha,beta-unsaturated ketones with a cinchona alkaloid catalyst
The simple alpha,beta-unsaturated ketones and 2-pyrones are readily available and synthetically important dienophiles and dienes, respectively, for Diels-Alder reactions. However, both prove to be challenging substrates for catalylic asymmetric Diels-Alder reactors. By exploring a new catalysis strategy featuring cooperative catalysis with readily available cinchona catalysts, an unprecedented asymmetric Diels-Alder reaction of simple alpha,beta-unsaturated ketones with 2-pyrones has been successfully developed. With broad scopes for both reactants, the reaction provides a direct and versatile asymmetric access to a wide range of structurally novel bicyclic chiral building blocks amenable for further synthetic elaborations.