STEREOSELECTIVE INTERACTION OF OPTICALLY ACTIVE AMINO ACIDS AND ESTERS WITH (L-VALINE-N-MONOACETATO)COPPER(II)

Equilibrium constants for the coordination of optically active amino acídales (A−) and their esters (E) to (L-valine-N-monoacetato)copper(II), Cu(L-ValMA) + l- or d-A− ⇌ Cu(L-ValMA)(A−), have been determined. For leucine, phenylalanine, alanine, and serine, the value of Kf is 3.3-6.5 times larger for the l than for the d isomer. For valine the Kf value for the d enantiomer is 2.5 times greater than that for the l. For the ester, ethyl leucinate, the l isomer gives a Kf which is 3.4 times larger than that for the d ester. It has also been determined that the rate of hydrolysis of methyl leucinate and methyl phenylalaninate in the complexes, Cu(L-ValMA)(E), is higher for the D-amino acid ester than for the l isomer. The mechanisms and the origins of the stereoselective effects are discussed. © 1969, American Chemical Society. All rights reserved.