Pd(II)-Catalyzed Synthesis of Alicyclic[]-Fused Pyridines via C(sp)-H Activation of -Unsaturated -Acetyl Hydrazones with Vinyl Azides.

A new synthetic protocol for alicyclic[]-fused pyridines with complete regioselectivity from unsaturated -acetyl hydrazones and vinyl azides via Pd(II)-catalyzed C-H activation/cyclization/aromatization strategy has been described. A series of five- to eight-membered alicyclic[]-fused pyridines were prepared in a one-step manner with wide substrate scope and good functional group tolerance.