A Green [4 + 2] Annulation Strategy for the Synthesis of 1,4-Dihydroquinazolines from Aminobenzyl Phosphonium Salts and Benzamidine Hydrochlorides

1,4-Dihydroquinazolines are privileged scaffolds in medicinal chemistry, yet their synthesis often relies on costly metal catalysts or multistep procedures. Herein, we report a practical and environmentally benign one-pot strategy for the synthesis of 1,4-dihydroquinazolines through [4 + 2] annulation of aminobenzyl phosphonium salts (ABPS) with amidine hydrochlorides. In this process, the reaction is featured with easily available starting materials, broad substrate scope, and environmentally friendly conditions.