Benzoisothiazolone Organo/Copper-Cocatalyzed Redox Dehydrative Construction of Amides and Peptides from Carboxylic Acids using (EtO)3P as the Reductant and O2 in Air as the Terminal Oxidant

Carboxylic acids and amine/amino acid reactants can be converted to amides and peptides at neutral pH within 5-36 h at 50 degrees C using catalytic quantities of a redox-active benzoisothiazolone and a copper complex. These catalytic oxidation-reduction condensation reactions are carried out open to dry air using O-2 as the terminal oxidant and a slight, excess of triethyl phosphite as the reductant. Methyl phosphate is the easily removed byproduct. These simple-to-run catalytic reactions provide practical and economical procedures for the acylative construction of C-N bonds.