A facile synthesis of amide bond formation involving nonnucleophilic and hindered amines is reported. DCPDC found itself to be an economical reagent for amide synthesis by activation of carboxylic acid. The reaction proceeds via diester intermediate formed by reaction between carboxylic acid and DCPDC. The approach presents a broad range of substrate scopes with 39 examples given. Notably, the reaction works equally well on scale up providing the desired product in excellent yield without any purification. More interestingly, our preliminary results indicated retention of configuration for chiral amines and acids.
Patra et al. (Sun,) studied this question.