Polymeric Cinchona Alkaloids as Catalysts in the Enantioselective 2,2-Cycloaddition Reaction of Ketene and Chloral

Article abstract of DOI:10.1016/0957-4166(94)80160-6

Poly(cinchona alkaloid-co-acrylonitrile) 1a-d and poly(cinchona alkaloid acrylate) 2a-b catalyze the enantioselective cycloaddition of ketene to chloral for the preparation of (R)- and (S)-β-(trichloromethyl)-β-propiolactone.Copolymers 1a-d showed relatively lower catalytic activity with moderate enantioselectivity (22-59percent e.e.), while homopolymers 2a-b gave similar catalytic activity and enantioselectivity (60-94percent e.e.) compared to those of their monomeric alkaloids as catalysts.The polymeric effect was observed with poly(acryloyl quinidine) 2a as catalyst to get the best enantioselectivity of 94percent e.e. at the temperature -30 deg C.