A convenient and efficient transition-metal-free protocol for the synthesis of 3-alkyl quinoxalin-2(1H)-ones from the radical reaction of quinoxalin-2(1H)-ones with ethers was developed with moderate to good yields. The methodology shows broad substrate scope, excellent functional group tolerance, high atom economy and high efficiency, thus enabling the preparation of diverse potentially valuable 3-alkyl quinoxalin-2(1H)-one derivatives.

A facile TBHP-mediated direct oxidative coupling of quinoxalin-2(1H)-ones with arylaldehydes has been developed under metal-free conditions. This method provided a convenient and efficient approach to various 3-acylated quinoxalin-2(1H)-ones from readily available starting materials with excellent regioselectivity. This reaction proceeded efficiently under mild conditions over a broad range of substrates and with functional group tolerance.

An efficient copper-catalyzed protocol for the synthesis of hydroxyl-containing quinoxalin-2(1H)-ones from the radical reaction of quinoxalin-2(1H)-ones with alcohols was developed with moderate to good yields. Quinoxalin-2(1H)-ones were coupled with alkyl radicals through direct catalytic functionalization of the α sp³ C–H bond of alcohols. The methodology demonstrates a broad substrate scope, excellent functional group tolerance, high atom economy and high efficiency, thus enabling the preparation of diverse potentially valuable hydroxyl-containing quinoxalin-2(1H)-ones.

A facile transition-metal-free decarboxylative radical coupling reaction of α,α-difluoroarylacetic acids with quinoxalin-2(1H)-ones has been developed. This methodology provided a highly attractive approach to synthesize a series of difluoroarylmethylated quinoxalin-2(1H)-ones that contain various functional groups in moderate to good yields under mild conditions. Moreover, experimental studies reveal that the CF₂ group of α,α-difluoroarylacetic acids plays a vital role in this transformation.