Mixed anhydrides derived from carboxylic and amidophosphoric acids,(RO)(R'2N) P (O) OC (O) R'(1), undergo unimolecular fragmentation yielding carboxyamides, R'C (O) NR'2, and metaphosphate esters, ROPO2. The mechanism of the amino group transfer was studied for substrate 1 a (1, R= R'= Me; R'= Ph); solvent as well as substituent effects indicate little (if any) charge development in the transition state. The effects of solvents and Lewis acids on ...