Nonclassical Routes for Amide Bond Formation

Abstract

The present review offers an overview of nonclassical (e.g., with no pre- or in situ activation of a carboxylic acid partner) approaches for the construction of amide bonds. The review aims to comprehensively discuss relevant work, which was mainly done in the field in the last 20 years. Organization of the data follows a subdivision according to substrate classes: catalytic direct formation of amides from carboxylic and amines ( section 2 ); the use of carboxylic acid surrogates ( section 3 ); and the use of amine surrogates ( section 4 ). The ligation strategies (NCL, Staudinger, KAHA, KATs, etc.) that could involve both carboxylic acid and amine surrogates are treated separately in section 5 .

Electron‐Deficient Borinic Acid Polymers: Synthesis, Supramolecular Assembly, and Examination as Catalysts in Amide Bond Formation

“…The higher yields in the reactions with 3 b as the catalyst compared to 3 a are consistent with the results for the model compounds 4 a and 4 b . However, they are unexpected considering that both ortho ‐chlorophenyl boronic acid and bis( ortho ‐chlorophenyl) borinic acid have been reported to display superior catalytic activity and the importance of ortho ‐substituents in general is well document in the literature –. In addition, after an acid and base wash similar to that performed by Blanchet et al.…”

Synthesis of Amido Esters and Amido Phosphonates through Carbonylation of Diazo Compounds Followed by Nucleophilic Addition Reaction

“…[7][8][9][10] Because of its importance, several synthetic methods have been developed to prepare different types of amides, most of which start from carbonyl compounds and amines. [14][15][16][17] These known methods, however, are not fully suitable to the synthesis of amido esters and amido phosphonates because of their low functional-group tolerance. [14][15][16][17] These known methods, however, are not fully suitable to the synthesis of amido esters and amido phosphonates because of their low functional-group tolerance.…”

Direct amidation of esters with nitroarenes

“…1a). Catalytic methods are rare1112 and notable examples include a Zr(O t -Bu) 4 -HOAt system developed by Porco and co-workers (HOAt=1-hydroxy-7-azabenzotriazole)13 and a Ru-pincer system developed by Milstein and co-workers14. These reactions proceed via nucleophilic substitution at the acyl carbon and mostly work with strongly nucleophilic alkyl amines, while anilines are often not suitable reaction partners.…”