We report the efficient synthesis
of cycloalkyl-fused naphthalenes
through the [4 + 2]-cycloaddtion/decarboxylative aromatization of
alkyne-tethered aryne insertion adducts. These scaffolds were difficult
to synthesize using conventional reactions. The reaction proceeds
via the formation of a benzopyrylium intermediate followed by intramolecular
[4 + 2] cycloaddition and a subsequent decarboxylation pathway. This
method is also compatible with allene-tethered substrates to afford
similar products. In addition, the one-pot synthesis of polysubstituted
naphthalenes via aryne insertion/benzannulation has also been developed
in good yield.