Photo-Excited Nickel-Catalyzed Silyl-Radical-Mediated Direct Activation of Carbamoyl Chlorides To Access (Hetero)aryl Carbamides

Amide bonds connect the amino acids in proteins and exist as a prevalent structural motif in biomolecules. Herein, we have exploited the concept of cross-electrophile coupling by merging the photo-redox and transition-metal catalysis to construct carbamides from superabundant (hetero)aryl halides along with commercially feasible carbamoyl chlorides. The success of this method relies on the prior formation of Ni-II-aryl halide intermediates, which involves in a photoexcited Ni-halide homolysis event by energy transfer from aryl bromide and single-electron transfer from aryl chloride to assist generation of the vital carbamoyl radical. The breadth of application of this technique is demonstrated both in inter- as well as intramolecular routes for the synthesis of a plethora of (hetero)aryl carbamides with diverse functionalities, and biologically important benzolactams.

Automated summary

In this study, we have successfully constructed carbamides using the concept of cross-electrophile coupling by combining photo-redox and transition-metal catalysis. The method involves the prior formation of Ni-II-aryl halide intermediates through photoexcited Ni-halide homolysis, energy transfer from aryl bromide, and single-electron transfer from aryl chloride to generate carbamoyl radicals.