Phosphite-Promoted Generation of ortho -Quinodimethanes for Efficient and Scalable Benzannulation

The classical Cava benzannulation suffers from high temperatures and poor solvent tolerance. We report a mild, room-temperature alternative using diethyl phosphite as a nucleophile. With diisopropylethylamine, smooth debromination generates reactive ortho -quinodimethanes for [4 + 2] cycloaddition with various dienophiles (e.g., quinones, alkenes, alkynes). This protocol is scalable, operationally simple, and even compatible with benzyne at −78 °C, enabling efficient synthesis of diverse aromatic structures.