Regioselective iridium(I)-catalysed remote borylation of oxygenated naphthalenes

We present our investigations into the regioselective borylation and halogenation of polyoxygenated naphthalene systems that are key precursors to dimeric pyranonaphthoquinone natural products. A variety of oxygenated naphthalenes were successfully borylated with pinacolborane in high yield and excellent regioselectivity using [Ir(COD)OMe]2 and di-tert-butylbipyridine (dtbpy). The boronates were also readily transformed into the corresponding halides, opening new avenues for the preparation of advanced Suzuki coupling substrates useful for the synthesis of natural products.