A Synthetic Approach to β-Functionalized Naphtho[2,3]porphyrins.

A concise synthetic method has been developed to access functionalized naphtho[2,3]porphyrins through combining two sequence reactions involving a Heck-electrocyclization-aromatization sequence and a Wittig-Knovenegal sequence. Using this method, mononaphtho[2,3]porphyrin (NP-1), opp-dinaphtho[2,3]porphyrin (NP-2), and push-pull naphtho[2,3]porphyrin (NP-3) have been prepared. These naphtho[2,3]porphyrins displayed interesting optical and electrochemical properties. Excellent efficiencies of singlet oxygen generation were obtained for these naphtho[2,3]porphyrins.