Fig. 2. Coupling of chromone and benzene via sequential C–H activation. Palladation of benzene (40-fold excess) with Pd(OTFA)2 is marginally faster than for the C3-position of chromone; palladation of chromone by PhPd(OTFA) and subsequent reductive elimination: the C3-regioselectivity afforded by this mechanism is inconsistent with experiment. Structures are colored as follows: Pd (dark blue), F (light blue), O (red), C (grey), H (white).
