An Organocascade Kinetic Resolution

Products of a novel iminium-catalyzed oxa-Michael addition undergo a kinetic resolution by a subsequent enamine-catalyzed intermolecular reaction. This is a rare example of kinetic resolution by enamine catalysis and the first organocascade kinetic resolution. This resolution produces enantioenriched 2,6-cis-tetrahydropyrans and, notably, cascade products with absolute and relative configurations normally not observed using this diphenyl prolinol silyl ether. This resolution thus provides new insight into asymmetric induction in reactions employing this catalyst.