ISSN:
0009-2940
Keywords:
Palladium complexes
;
Rhodium complexes
;
α-Amino acids
;
2-Iminocarboxylate as ligand
;
Chiral glycine
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Metal Complexes of Biologically Important Ligands, LXVII[1]. - Synthesis of α-Amino Acids from Palladium(II)- and Rhodium(III)-Coordinated Imines and Oximes of α-OxocarboxylatesThe bis-chelate complexes Pd[O2CC(R1)=NOR2]2 (1) and Pd[O2CC(R1)=NR2]2 (2, R2 optically active substituent) are synthesized by template condensation of an α-oxocarboxylic acid with a hydroxylamine or amine component, respectively. Similarly, the Rh(III) complexes Cp*Rh(Cl)[O2CC(R)=N(CHMePh)] (3a: R = H, 3b: R = Me) were obtained from α-oxocarboxylic acids and optically active 1-phenylethylamine. Catalytic hydrogenation of 1 and 2 gives directly the free α-amino acids with, in case of 2, ee's between 0 and 36%. Nucleophilic attack by the carbanions of RC(O)CH2CO2Et and H2NCH(CO2Et)2 at the imino carbon atom of 3a leads to the α-amino carboxylato complexes 4 and 5. - Compounds 4a and 5 have been characterized by X-ray diffraction. Reaction of 3a with NaBH4 or NaBD4 followed by decomposition of the complex with HCl yields N-substituted glycine and N-substituted α-deuterio-glycine, respectively. The diastereoselectivity (70:30) of the α-deuteration could be determined by NMR spectroscopy.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19931261113
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