The asymmetric cyclisation of substituted pent-4-enals by a chiral rhodium phosphine catalyst
Abstract
Treatment of the racemic disubstituted pent-4-enals (1) and (2) at ca. 150 °C with the chiral complex [Rh(chiraphos)2]Cl [chiraphos = 2S,3S-bis(diphenylphosphino)butane] results in a cyclisation reaction and catalytic asymmetric synthesis of the 2,2- and 3,3-disubstituted cyclopentanones (3) and (4), respectively.