A new and efficient synthesis of imidazo[1,5-a] pyridine derivatives by a tandem aza-Wittig / electrocyclic ring closure of N-vinylic phosphazenes

Article abstract of DOI:10.1016/0040-4020(95)00083-K

Imidazo[1,5-a]pyridines 1 are prepared by reaction of N-vinylic phosphazene 3, obtained from phosphorus ylide 5 and 2-cyanopyridine 4, with aldehydes. Formation of fused heterocycles 1 can be explained through aza-Wittig reaction of phosphazene 3, followe