Regioselective synthesis of 1,2,4,5-tetrasubstituted pyridines from Baylis–Hillman adducts via consecutive [3+2+1] annulation protocol

An efficient synthetic method of poly-substituted pyridines was developed. Various poly-substituted pyridines were prepared from the combination of Baylis–Hillman adducts (3 carbons), activated methylene compounds (2 carbons) and ammonium acetate (1 nitrogen) via [3+2+1] annulation protocol in good yields, regioselectively.