Enantioselective hydrogenation of trifluoroacetophenone over polymer-stabilized platinum nanoclusters

The enantioselective hydrogenation of 2,2,2-trifluoroacetophenone to (R)-1- phenyl-2,2,2-trifluoroethanol was investigated over finely dispersed polyvi nylpyrrolidone-stabilized platinum nanoclusters modified with cinchonidine. It was shown that the modifier, apart from inducing enantioselectivity, ha s a considerable rate-promoting effect on this reaction. Different from wha t had been reported for the conventional supported platinum catalyst, polyv inylpyrrolidone-stabilized platinum nanoclusters were demonstrated to be as sociated with structure insensitivity for this reaction. The favorable reac tion pressure was 2.0 MPa with a mixture of o-dichlorobenzene and ethanol ( v/v = 20/1) as solvent. Moderate cinchonidine concentration was also advant ageous for enantiodifferentiation. (C) 2001 Elsevier Science B.V. All right s reserved.