Chemical Transformations of Donor-acceptor Cyclopropanes With Conjugated Diacetylenes in the Presence of GaCl3

The reaction of 1,2-zwitterionic complexes of 2-arylcyclopropane-1,1-dicarboxylates (ACDC), generated using gallium trichloride, with symmetrically substituted diacetylenes was studied. The reaction occurs via a cascade addition/annulation/elimination pathway involving both triple bonds to form substituted 1,1'-binaphthalenes in up to 50% yields. The regioselectivity of this process was studied, and it was shown that binaphthalenes formed exclusively as 1,1'-regioisomers.