A kinetic study of phosphinic carboxylic mixed anhydrides
Abstract
Using 32.4 MHz 31P n.m.r. spectroscopy, disproportionation of a series of phosphinic carboxylic mixed anhydrides derived from protected α- amino acids has been studied both as a function of the substituents at phosphorus and structure of the α-amino acid being activated. It was found that the rates of disproportionation were insignificant from a preparative aspect compared with aminolysis at 0 °C.