Introduction of Phosphinine Ring into Aromatic Systems via Alkyne Cyclization

Abstract

Recently developed synthetic protocols for the preparation of λ3-phosphanaphthalenes have broadened the general scope of organophosphorus chemistry, but a versatile protocol is still missing. Here, we describe a scalable synthetic approach for the construction of various substituted phosphanaphthalenes. We have obtained 11 derivatives through rigorous study and have demonstrated the robustness of this method. The optical properties of these phosphorus compounds and their aza and carbo analogues have been experimentally compared. Here, we show the power of the method in extending the synthesis to even larger polycyclic aromatic systems with embedded phosphine rings toward its potential applicability to materials science.