Photoinduced 1,3‐Dipolar Cycloadditions of Cyclic Enones and 2,5‐Disubstituted Tetrazoles: An Unprecedented Pathway to Polysubstituted Pyrazolines and Pyrazoles.
Résumé
We report herein the syntheses of original pyrazolines and pyrazoles through 1,3‐dipolar cycloaddition cyclic enones with 2,5‐disubstituted nitrile imines achieved via photochemical activation 2,5‐diaryl substituted tetrazoles. Monitoring reactions, similar to imine‐mediated tetrazole‐ene cycloadditions (NITEC), could be performed by means UV‐vis absorption emission measurements. The presence or absence substituents in alpha position ketone function makes it possible direct these reactions towards selective formation pyrazolines. choice tetrazoles proved crucial for fluorescence properties polycyclic derivatives obtained.