Selective hydrogenation of PhCHCHCOMe to the unsaturated alcohol catalysed by [IrH3(PR3)3](R = alkyl or aryl)

Abstract

Selective hydrogenation of benzylideneacetone (PhCHCHCOMe) catalysed by iridiumphosphine systems prepared in situ is reported. Depending on the steric properties of the phosphine employed and the P:lr ratio, different species are formed in solution, as evidenced by n.m.r. spectroscopy. [IrH₅(PR₃)₂](R = alkyl or aryl) is a catalyst for the hydrogenation of the carbon–carbon double bond, whereas [IrH₃(PR₃)₃] catalyses the reduction of the carbonyl group with a selectivity up to 100%.