Enantioselective synthesis of [9]- and [11]helicene-like molecules: double intramolecular [2+2+2] cycloaddition.

The enantioselective synthesis of completely ortho-fused [9]- and [11]helicene-like molecules has been achieved through a rhodium-mediated, intramolecular, double [2+2+2] cycloaddition of phenol- or 2-naphthol-linked hexaynes. Crystal structures and photophysical properties of these [9]- and [11]helicene-like molecules have also been disclosed.