Rhodium(III)-Catalyzed C-C and C-O Coupling of Quinoline N-Oxides with Alkynes: Combination of C-H Activation with O-Atom Transfer

[Cp* Rh-III]-catalyzed C-H activation of arenes assisted by an oxidizing N-O or N-N directing group has allowed the construction of a number of hetercycles. In contrast, a polar N-O bond is well-known to undergo O-atom transfer (OAT) to alkynes. Despite the liability of N-O bonds in both C-H activation and OAT, these two important areas evolved separately. In this report, [Cp* Rh-III] catalysts integrate both areas in an efficient redox-neutral coupling of quinoline N-oxides with alkynes to afford alpha-(8-quinolyl) acetophenones. In this process the N-O bond acts as both a directing group for C-H activation and as an O-atom donor.