Peptide Synthesis by Oxidation-Reduction Condensation. I. Use of NPS-Peptides as Amino Component

Sulfenamides were found to react readily with soft nucleophiles in the presence of active hydrogen compounds. A new method for the synthesis of carboxamide from metal carboxylate, sulfenamide and tertiary phosphine was developed. The effects of metal component were examined. Copper(II) salts gave the best result. In a similar way, peptides were synthesized by the reaction of copper(II) salts of acylamino acid, or free acylamino acid in the presence of cupric chloride and triethylamine, with NPS-amino acid derivatives and triphenylphosphine. When organo-mercuric compounds such as dianisylmercury were used in place of cupric chloride and triethylamine in the above reaction, almost complete retention of configuration was observed by the Young test.