Lewis‐Acid‐Catalysed Activation of Nitriles: A Microwave‐Assisted Solvent‐Free Synthesis of 2,4‐Disubstituted Quinazolines and 1,3‐Diazaspiro[5.5]undec‐1‐enes

다국어 초록 (Multilingual Abstract)

Two different modes of cyclization take place to synthesize quinazoline, quinazolinone, and 1,3‐diazaspiro[5.5]undec‐1‐ene derivatives through the Lewis‐acid‐catalysed activation of both aliphatic and aromatic nitriles in a single‐step, solvent‐free, and transition‐metal‐free reaction. An amidine is expected to form as an intermediate; this then undergoes intramolecular cyclization in a one‐pot reaction sequence. The reaction is carried out under microwave irradiation using trimethylsilyltrifluoromethane sulfonate (TMSOTf) as a catalyst and nitriles as a nitrogen source with the respective reaction partners.
A single‐step, solvent‐free, and transition‐metal‐free reaction for the synthesis of quinazolines/quinazolinones starting from 2‐amino carbonyl compounds, and of 1,3‐diazaspiro[5.5]undec‐1‐ene derivatives starting from N‐tosyl‐2‐(cyclohexenyl)ethylamines, is reported. The Lewis‐acid‐catalysed activation of nitriles is a key feature of this reaction.