• Chem. Lett. , 575 (1977).
• Chem. Lett. , 1159 (1975).
• Chem. Lett. , 49 (1976).
• Chem. Lett. , 1045 (1975).
• Synthesis of esters: Chem. Lett., 1163 (1975); Bull. Chem. Soc. Jpn., 50, 1863 (1977); macrolides: Chem. Lett., 49 (1976); Tetrahedron Lett., 30, 3209 (1989); and strained, trans-fused -lactones: Synthesis, 493 (1983). Formation of?-lactams from ?-amino acids: Synthesis, 210 (1979); Chem. Lett., 1465 (1984), or from carboxylic acids and imines: Tetrahedron Lett., 32, 581 (1991); cyclization of a macrocyclic amide: J Am. Chem. Soc., 111, 1157 (1989). Coupling of carboxylic acids with N,O-dimethylhydroxylamine gives the Weinreb amide: Synth. Commun., 25, 1255 (1995).
•
Carboxylic acids are coupled with nucleophiles, YH, according to the following scheme:

• Applications include:
• Useful reagent in a wide variety of dehydrative coupling reactions. For a review of the chemistry of this and related reagents, see: Angew. Chem. Int. Ed., 18, 707 (1979). For peptide reagents, see Appendix 6.
• Conversion of thioureas to carbodiimides: Chem. Lett., 575 (1977); in the presence of a primary amine the guanidine is formed: J. Org. Chem., 62, 1540 (1997). Generation of ketenes from carboxylic acids: Synlett, 36 (1989).