Improved synthesis of proline-derived Ni(II)-complexes of glycine, versatile chiral equivalents of nucleophilic glycine for general asymmetric synthesis of a-amino acids

ORGN 532

Tomas U. Boettiger, Shawna B. Bolene, Hisanori Ueki, Trevor K. Ellis, Collin H. Martin, and Vadim A. Soloshonok. Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, OK 73019-3051

Synthetically practical and operationally convenient method for preparing (S)-2-[N-(N’-benzylprolyl)amino]benzophenone (BPBP) and hitherto unknown (S)-2-[N-(N’-benzylprolyl)amino]-4-methylbenzophenone (4-Me-BPBP), (S)-2-[N-(N’-benzylprolyl)amino]-5-nitrobenzophenone (5-NO2-BPBP) and their corresponding Ni(II)-complexes with glycine [GlyNi(II)BPBP], currently being widely used as a chiral equivalent of nucleophilic glycine, and new analogs [GlyNi(II)-4-Me-BPBP], [GlyNi(II)-5- NO2-BPBP] are described. The key step of the method is the synthetically efficient amid bond formation between the corresponding o-aminobenzophenones, which feature significant steric shielding and low nucleophilicity of the amino function, and sterically constrained (S)-N-benzylproline (BP). The incorporation of convenient reaction conditions and high chemical yields make this method attractive for the large scale production of the fore mentioned Ni(II) complexes.

Bioorganic, Molecular Recognition, Asymmetric Reactions and Syntheses 11:00 AM-1:00 PM, Wednesday, September 10, 2003 Javits Convention Center -- Hall 1B/1C, Poster Division of Organic Chemistry The 226th ACS National Meeting, New York, NY, September 7-11, 2003