Synthesis of Benzo[c]azepine-1,3(2H)-diones via C-H Alkylation/Cyclization with α,β-Unsaturated Acyl Fluorides

Transition-metal-catalyzed directed C-H functionalization reactions are a powerful method to construct N-heterocycles. However, compared to the formation of five- and six-membered rings, that of seven-membered rings has been much less explored. Here, the synthesis of benzo[c]azepine-1,3(2H)-diones is described, which are benzene-fused seven-membered imides, from hydroxamates and alpha,beta-unsaturated acyl fluorides via C-H activation using a Cp*Rh(III) catalyst. Under mild reaction conditions, this reaction affords benzo[c]azepine-1,3(2H)-diones that bear a substituent at the 5-position.