Communication
Conformationally Flexible Biphenyl-phosphane Ligands for Ru-Catalyzed Enantioselective Hydrogenation
First published: 24 February 1999
Citations: 232
Abstract
Stereomutation of a BIPHEP/RuCl2/diamine complex (shown schematically) is possible because of the conformational flexibilty of BIPHEP ligands. The result is an asymmetric activation in the Ru-catalyzed hydrogenation of carbonyl compounds to optically active alcohols. Whereas a racemic BINAP/RuCl2 complex with a chiral diamine activator gives a 1:1 mixture of two diastereomers, unequal amounts of the diastereomers can be produced from a BIPHEP/RuCl2 complex and a chiral diamine. Ar=3,5-dimethylphenyl, BINAP=2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl, BIPHEP=2,2′-bis(diarylphosphanyl)biphenyl.
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