Catalytic Asymmetric Cycloaddition of Carbon Dioxide and Propylene Oxide Using Novel Chiral Polymers of BINOL-Salen-Cobalt(III) Salts

Four new chiral polymers of BINOL-Salen-cobalt(III) salt complexes have been designed, synthesized and applied to the direct fabrication of chiral propylene carbonate from racemic propylene oxide. The (R/S)-polymer catalyst 2 and (SIR)-polymer catalyst 4 exhibit better enantioselectivity than the (R/R)-polymer catalyst 1 and the (S/S)-polymer catalyst 3 and have been recovered and reused more than ten times without loss of activity and enantioselectivity.