Amino Acids and Peptides. X. Phosphorus in Organic Synthesis. V. On the Mechanism for the Peptide Synthesis by Diphenyl Phosphorazidate

The peptide bond formation reaction by some analogs of diphenyl phosphorazidate (DPPA) was investigated, proving that DPPA is much superior in the Young test to diethyl phosphorazidate, di-p-nitrophenyl phosphorazidate, dimorpholyl phosphorazidate, and diphenyl phosphorochloridate. Some spectroscopic investigations on the DPPA method were also made. Possible mechanisms for the DPPA method are presented in Chart 1.