Synthesis of phthalazines
A one-pot strategy allows the synthesis of phthalazines and pyridazino-aromatics starting from aromatic aldehydes. A variety of substituents ranging from electron withdrawing to donating is tolerated furnishing the desired 1,2-diazine in good to excellent yields. A subsequent bidentate Lewis acid catalyzed inverse electron-demand Diels-Alder (IEDDA) reaction opens a novel two-step entry into substituted naphthalenes, such as Naproxen.
S. N. Kessler, H. A. Wegner, Org. Lett., 2012, 14, 3268-3271.