Asymmetric Synthesis and Photophysical Properties of Benzopyrano- or Naphthopyrano-Fused Helical Phosphafluorenes

Enantioenriched benzopyrano- and naphthopyrano-fused helical phosphafluorenes have been synthesized by the rhodium-catalyzed enantioselective double [2 + 2 + 2] cycloaddition of dialkynyl phosphorus compounds with phenol- or naphthol-linked tetraynes. Photophysical properties of these phosphafluorenes are also disclosed.