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-rert-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. (C) 2012 Elsevier Ltd. All rights reserved.