Cross-dehydrogenative coupling of aldehydes with N-hydroxyimides: An efficient and straightforward route to N-hydroxyimides esters

Esterification of N-hydroxyimides to corresponding active esters (N-hydroxyimide esters) is one of the most important organic transformations not only for their importance as versatile intermediates for amides and esters but also their use as coupling partners in various C-S, C-C and C-N coupling reactions. Therefore, there is continuing interest in the development of efficient, practical, and straightforward methodologies for their construction. Nowadays, cross-dehydrogenative coupling reactions, which combine two unmodified C(X)–H (X = heteroatom) bonds for the fabrication of new C(X)–C(X) bonds, are recognized as a fundamental synthetic tool for highly atom-economical synthesis of a wide variety of organic compounds. Along this line, recently, several procedures have been reported for the synthesis of N-hydroxyimide esters through the oxidative C-O coupling of with aldehydes with N-hydroxyimides. This review highlights recent progresses in this interesting research field.