Decarboxylative C(sp3)–N cross-coupling via synergetic photoredox and copper catalysis

Amines are a quintessential moiety in bioactive molecules, pharmaceuticals and organic materials. Transition-metal-catalysed C–N coupling of aryl electrophiles has been established as a powerful and reliable method for amine synthesis. However, the analogous C–N coupling of alkyl electrophiles is largely under-developed due to the decomposition of metal alkyl intermediates by β-hydrogen elimination and difficulty in C(sp3)–N reductive elimination. Here, we provide a general strategy for amination of alkyl electrophiles by merging photoredox and copper catalysis. Photoredox catalysis allows the use of alkyl redox-active esters, recently established as a superior class of alkyl electrophiles, whereas copper catalysis enables C(sp3)–N cross-coupling. Decarboxylative amination can be used for the synthesis of a diverse set of alkyl anilines with high chemoselectivity and functional-group compatibility. Rapid functionalization of amino acids, natural products and drugs is demonstrated. While methods for arylation of amines are well established, alkylation is a less well-developed process. Here, Hu and co-workers report amine alkylation using redox-active esters, using a combination of photoredox catalysis to generate the active electrophile and copper catalysis for the cross-coupling.