Novel Approach to Chlorins and Bacteriochlorins: [8π+2π] Cycloaddition of Diazafulvenium Methides with Porphyrins
New and unprecedented [8π+2π] cycloaddition of diazafulvenium methides with porphyrins and chlorins is reported. The synthetic methodology allowed the access to a new type of 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused chlorins and bacteriorins in a selective fashion.