Chemodivergent dearomatization of benzene-linked O-oxime esters via EnT-induced radical cross-coupling

Radical-mediated dearomatization strategies offer a blueprint for building value-added and synthetically valuable three-dimensional skeletons from readily available aromatic starting materials. Herein, we report a novel strategy by leveraging benzene-linked O-oxime esters as triply functionalized precursors to form two distinct persistent radicals under a chemodivergent pathway. These radicals then couple with a cyclohexadienyl radical for either carboamination or carbo-aminoalkylation. Remarkably, a series of 4-(2-aminoethyl)anilines derivatives featuring all-carbon quaternary centers, along with the formation of four different types of chemical bonds, are efficiently constructed through a unique rearomatization cascade in the carboamination. Importantly, employing DMPU as the hydrogen atom transfer (HAT) donor strategically diverts the reaction pathway from the C-N bond formation towards the C-C bond formation. Our mechanistic explorations support a sequential HAT/energy transfer (EnT)/HAT cascade as the key stage for carbo-aminoalkylation involving the N-center iminyl radical. Significantly, this work demonstrates the elegant expansion of divergent C-N and C-C bond formation using the imine moiety within O-oxime esters as the bifunctional reagent, and it broadens the chemical space of both benzenes and O-oxime esters in radical-mediated transformations.