Enantioselective synthesis of tetrahydrofuran spirooxindoles via domino oxa-Michael/Michael addition reaction using a bifunctional squaramide catalyst.

An enantioselective approach for the synthesis of tetrahydrofuran spirooxindoles via domino oxa-Michael/Michael addition reaction of γ-hydroxyenones to isatylidene malononitriles, using a cinchona derived bifunctional squaramide catalyst has been developed. The methodology is the first success of enantioselective oxa-Michael addition to isatylidene malononitriles. The spiro products were obtained in excellent yields with moderate to good enantio- and diastereoselectivities. Scale-up of the reaction and synthetic transformation of the spiro product into structurally complex molecules have been performed.

Asymmetric Multifunctional Modular Organocatalysis: One-Pot Direct Strategy to Enantiopure α,ß-Disubstituted γ-Butyrolactones.

A simple and efficient approach to enantioenriched α,ß-disubstituted γ-butyrolactones has been developed through multifunctional modular organocatalysis in a highly enantioselective (>99% ee) and diastereoselective (>30:1) manner following a one-pot sequential Michael-hemiacetalization-oxidation reaction. The catalytic process has great substrate compatibility, and the products have been transformed to synthetically useful molecules. The methodology has also been applied to the formal synthesis of (+)-Pilocarpine.