The Oxidation of Amides to Imides: A Powerful Synthetic Transformation

Abstract

Despite appearing to be a conceptually simple transformation, the oxidation of amides to imides is far from straightforward, primarily due to the inertness of amides toward electrophilic oxidants. This perspective provides an overview of the development of reaction conditions capable of effecting this oxidation. The application of amide to imide oxidations in the fields of medicinal chemistry and natural product synthesis, as well as the advantages and limitations of the various oxidation conditions, is also discussed.

Versatile and Sustainable Synthesis of Cyclic Imides from Dicarboxylic Acids and Amines by Nb2O5 as a Base‐Tolerant Heterogeneous Lewis Acid Catalyst

“…The typical methods1, 3–5 are the dehydrative condensation of an anhydride with an amine at high temperatures or in the presence of an excess amount of promoter (Lewis acid, base, dehydrating agent, or ionic liquids)3 and the cyclization of an amic acid with the help of acidic reagents,4 which suffer from low atom efficiency and production of byproducts. Although new synthetic routes from nitriles,6 halides,7 alkyne,8 pyridin‐2‐ylmethylamines,9 aryl boronic acids,10 aliphatic amides,11, 12a cyclic amines,12b isocyanates,13 and phthalimide14 using transition‐metal catalysis (carbonylation, oxidation, etc. )6–13 or excess amounts of I(III) oxidant14 have been developed, these homogeneous catalytic methods have drawbacks of narrow substrate scope, needs of various additives or toxic reagents (CO), no reusability of expensive catalysts, and difficulties in catalyst/products separation.…”

Ruthenium Tetroxide and Perruthenate Chemistry. Recent Advances and Related Transformations Mediated by Other Transition Metal Oxo-species

“…Accounts of some aspects of the RuO 4 chemistry have previously been published [75,76,77,78] but no comprehensive review has been published in the last years. In the present account we report an up-to-date picture of the RuO 4 chemistry covering the literature in the period 2006-2013, with a special focus on the oxidative chemistry of alkenes and polyenes, by also discussing some aspects of the relevant processes not fully dealt with previously.…”

CuCl/TMEDA/nor-AZADO-catalyzed aerobic oxidative acylation of amides with alcohols to produce imides

“… 3 To date, various synthetic methods for imides have been developed, including (i) acylation of amides with activated forms of carboxylic acids, such as acid chlorides, anhydrides, and esters ( Scheme 1a ); 4 (ii) Mumm rearrangement of isoimides ( Scheme 1b ); 5 (iii) oxidative decarboxylation of amino acids ( Scheme 1c ); 6 (iv) carbonylative coupling of aryl halides and amides ( Scheme 1d ); 7 and (v) oxygenation of amides ( Scheme 1e ). 8 Among these methods, acylation of amides with acyl chlorides in the presence of (super)stoichiometric amounts of strong bases is the most frequently utilized. However, this antiquated acylation method has a limited substrate scope and often suffers from low synthetic and atom efficiencies due to the use of pre-functionalized substrates ( i.e.…”