Regioselective Annulation of Unsymmetrical 1,2‐Phenylenebis(diaryl/diheteroarylmethanol): A Facile Synthesis of Anthracene, Tetracene, and Naphtho[b]thiophene Analogues

Abstract

AbstractA systematic study on the regioselective cyclization of benzene‐ and naphthalene‐based unsymmetrical diols with HBr (33 %) in acetic acid at room temperature led to the formation of annulation products. By using this method, synthesis of a wide variety of anthracene, tetracene and naphtho[b]thiophene analogues was achieved in good to excellent yields. By employing HBr (33 %) in acetic acid as a catalyst for regioselective cyclization of unsymmetrical diols was very facile and devoid of commonly encountered dihydroisobenzofuran formation.