Highly stereoselective and oxydative addition of protic molecules to iridium(I) complexes and asymmetric hydrogenation of prochiral imines.

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Mononuclear iridium(III) complexes of general formula IrX(H)(O_2CR)[(S)-binap](2, R=CH_3 ; 3,R=Ph ; 4,R=C_6H_4CH_3-p ; a, X=Cl ; b, X=Br ; c, X=I) were prepared by one-pot reaction of [Ir(μ-X)(cod)]_2 with 2 equiv of (S)-BINAP [=2,2'-bis(diphenylphosphino)-1,1'-binaphthyl] and an excess of the corresponding carboxylic acid in toluene. The structure of (S)-2-4 bearing an (S)-BINAP was confirmed to be OC-6-23-A (Λ-conformation) by X-ray analysis of (S)-4a-c. In this reaction, the iridium(I) complex {Ir(μ-Cl)[(S)-binap]}_2 [(S)-5a] and pentacoordinated iridium(I) complexes IrX(cod)[(S)-binap] [(S)-7b, X=Br ; (S)-7c, X=I] were generated prior to the oxidative addition of carboxylic acid. Cationic dinuclear iridium(III) complexes of general formula [{Ir(H)[(S)-binap]}_2(μ-X)_3]X [(S)-8 : a, X=Cl ; b, X=Br ; c, X=I] were prepared, and their cationic bifacial octahedral dinuclear structure was characterized by spectral data and combustion analysis. The anionic portion of these complexes could … More be replaced by NaPF_6, leading to the corresponding PF_6 salts [{Ir(H)[(S)-binap]}_2(μ-X)_3]PF_6 [(S)-8 : d, X=Cl ; e, X=Br ; f, X=I]. Iodo-acetate complexes of p-TolBINAP (=2,2'-bis(di-4-tolylphosphino)-1,1'-binaphthyl) [(S)-9c] and SYNPHOS [=2,2',3,3'-tetrahydro(5,5'-bi-1,4-benzodioxin)-6,6'-diyl]bis(diphenylphosphine)] [(S)-10c] were also prepared according to the method used for the BINAP complex (S)-2c and were characterized spectroscopically. Cationic dinuclear complexes of p-TolBINAP [(S)-11c] and SYNPHOS [(S)-12c] were also generated. Using these complexes, the effect of halide variation was studied by asymmetric hydrogenation of 2-phenylpyrrolidine (13) and 2-phenyl-4,5,6,7-tetrahydro-3H-azepine (15) along with 2-phenylquinoline (16), and the results indicated that iodide complexes were better catalyst precursors for catalytic activity than the corresponding chloride and bromide complexes, but were not superior in enantioselectivity. I have acquired three patents. The titles of patents are as follows, a : Method for preparation of optically active neutral rhodium-phosphine complexes as asymmetric synthesis catalysts. b : Preparation of iridium complexes as catalysts for the synthesis of optically active amines. c : Preparation of optically active phenylamines. Less