Metal catalysed transamidation

Early accounts of non-metal catalysed transamidation used gaseous boron trifluoride with aeetamide and aniline vapor. However, recent boron-based reagents, although used in excess, work under eonsiderably milder conditions and tolerate a wide variety of functional groups. Sheppard and co-workers tris(trifluoroethyl)borate reagent, also highlighted for direct amide bond forming reactions between carbo>ylic acids and amines, is active for... 

---