Regioselective Synthesis of 2- or 2,7-Functionalized Pyrenes via Migration.

A simple method for the preparation of 2- or 2,7-functional pyrenes from 1- or 1,6-substituted derivatives is reported. The synthesis involves the unexpected 1,2-phosphinyl migration in an AlCl3/NaCl melt. The structure of the product has been unambiguously confirmed by X-ray crystallography. We also demonstrated that further functionalization of pyrene through C-P bond activation is possible. These 2,7-positions are difficult to derivatize otherwise.