Synthesis of new cationic BINAP–ruthenium(II) complexes and their use in asymmetric hydrogenation [BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl]

Reaction of [RuX2(arene)]2(1) and (S)-BINAP gives cationic BINAP–ruthenium complexes of the formula {RuX(arene)[(S)-binap]} Y (2)(X = Cl, Br, and l; Y = Cl, Br, l, BF4, and BPh4; arene = C6H6 and p-MeC6H4CHMe2) which are efficient catalyst precursors for enantioselective hydrogenation of various prochiral alkenic and ketonic substrates [BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl]; a crystal structure of (2)(with X = Cl, Y = BF4) was obtained.