Amide bond formation: beyond the myth of coupling reagents

the approach of the amine via hydrogen bonding (Scheme 3). However, HOBt can yield by-products, thus it catalyses the formation of diazetidine 11 (Scheme 4).26 In 1994, Carpino reported a related additive, 1-hydroxy-7-azabenzotriazole (HOAt) 12 (Fig. 2), which was even more efficient than HOBt 9 in terms of yield, kinetics and reduced ................
................