Dynamic Kinetic Asymmetric Transformation of Racemic Diastereomers: Diastereo? and Enantioconvergent Michael–Henry Reactions to Afford Spirooxindoles Bearing Furan?Fused Rings

Dynamic kinetic asymmetric transformation (DYKAT) reactions of racemic diastereomer mixtures that afford the products as essentially single diastereomers with high enantioselectivities are described. We demonstrated DYKAT in diastereo- and enantioselective synthesis spirooxindoles bearing furan-fused rings. The starting materials DYKAT, dihydrobenzofuranone derivatives, were synthesized mixtures, these transformed to spirooxindole derivatives yields through Michael–Henry cascade nitrostyrenes under organocatalytic conditions. In reactions, regardless stereochemistry materials, all four isomers enantioselectivities, new chiral centers created.