ASYMMETRIC TRANSFORMATION OF ALPHA-AMINO-ACIDS PROMOTED BY OPTICALLY-ACTIVE COBALT(III) COMPLEXES .2. N-METHYLALANINATOCOBALT(III) COMPLEXES WITH TETRAMINES

The preparation and structural assignments of N-methyl-(S)-And-(R)-Alaninatocobalt(III) complexes with a few ehiral derivatives of 2,3,2-Tet (= 3,7-diazanonane-I ,9-diamine) and triethylenetetramine are described. The hydroxide ion-catalyzed epimerizations of these complexes are examined at p1-I 10. In the N-methylalaninato complexes the isomer ratio for A-S/A-R ranged from 76/24 to 90/10. In the most favorable case where tetramine is 2(S) l0(S)-4,8-diazaundeeane-2,10-diamine (abbreviated as 2(S) lO(S)-Me,-2,3,2-Tet) the energy differences among the four possible diastereomers are discussed in relation to the prediction from strain energy minimization calculations. © 1980 The Chemical Society of Japan.