Construction of C(sp2 )-C(sp3 ) Bond between Quinoxalin-2(1H)-ones and N-Hydroxyphthalimide Esters via Photocatalytic Decarboxylative Coupling.

A novel visible-light-driven decarboxylative coupling of alkyl N-hydroxyphthalimide esters (NHP esters) with quinoxalin-2(1H)-ones has been developed. This C(sp2 )-C(sp3 ) bond-forming transformation exhibits excellent substrate generality with respect to both the coupling partners. Of note, a series of 3-primary alkyl-substituted quinoxalin-2(1H)-ones that were difficult to synthesize by previous methods could be obtained in moderate to excellent yields. Additionally, the mild conditions, easy availability of substrates, wide functional group tolerance and operational simplicity make this protocol practical in the synthesis of 3-alkylated quinoxalin-2(1H)-ones.