Synthesis of Multisubstituted Arylnitriles via Tf2O-Mediated Benzannulation of Enaminones with Acylacetonitriles

A novel and efficient method for the synthesis of multisubstituted arylnitriles via Tf₂O-mediated [3 + 2 + 1] benzannulation of enaminones and acylacetonitriles has been developed. This reaction proceeds under mild conditions with excellent functional group compatibility. Mechanistic studies have revealed that the cyclization involves two consecutive nucleophilic additions, followed by a cascade Knoevenagel condensation and aromatization. Additionally, trifluoromethanesulfonate 6 has been identified as a crucial intermediate in this process.