Amination reactions phosphorus coupling products

In these reactions, hydrolysis of diphenyl and triaryl phosphites to monoaryl phosphites and phenol was coupled by dehydration between carboxylic acids and amines or alcohols to the corresponding amides and esters. Therefore, the reaction can be generalized as a hydrolysis-dehydration reaction (Scheme 2). The concept of the hydrolysis-dehydration reaction using phosphites has been drown to be applicable also to reactions with other phosphorus compounds such as phosphinites, phos-phonites and phosphorates s Aryl esters of these phosphorus compounds are effective as condensing agents in the production of carboxylic amides and esters (from carboxylic acids and amines or alcohols, respectively) whereas alkyl esters are ineffective (Eqs. (1-3)) ... 

In all the entries but the first two, the phosphorus atoms contain two aryl groups. Some crowded diphosphine boranes have also been reported (entries 2, 6, 10, 14 and 16-21). In general, good yields for the coupling reaction are observed, even in the latter cases. The diphosphine boranes are obtained as enantiomerically pure white solids or oils, which can be easily deboronated by amines. The diphosphinite borane of entry 1 also deserves some comment because another product could have been formed (Scheme 4.40). 

---