Regioselective Halogenation and Dimerization of Alkoxynaphthalenes with Alumina- or Kieselguhr-supported Copper(II) Halides†

The reaction of 1-alkoxynaphthalenes 1 with alumina-supported copper(II) bromide or copper(II) chloride gave dimers, 4,4′-dialkoxy-1,1′-binaphthyls 3, as major products, and with Kieselguhr-supported copper(II) bromide afforded 1-bromo-4-alkoxynaphthalenes 2, while the reaction of 2-alkoxynaphthalenes 4 with alumina- or Kieselguhr-supported copper(II) bromide gave preferentially 1-bromo-2-alkoxynaphthalenes 5.