Cerium(III)-Catalyzed Facile Synthesis of Dihydrobenzofuran-Tethered Pyridines and Dihydroquinolin-5(6H)-ones from β-Enaminones

A series of novel dihydrobenzofuran-tethered pyridines, dihydroquinolin-5(6H)-ones, and indeno[1,2-b]pyridin-5-ones were synthesized in very good yields by CeCl3 center dot 7H(2)O-NaI catalyzed one-pot condensation of variants of the Bohlmann-Rahtz reaction, viz. beta-enaminones derived from 7-acetyldihydrobenzofurans, acyclic and cyclic 1,3-dicarbonyls, and ammonium acetate. The protocol offers the advantages of easily accessible substrates, shorter reaction times, and easy work-up with a readily available catalyst. Further more, dihydrobenzofuran-substituted 2-(chloromethyl)pyridine was derivatized to its synthetic hybrid by reacting with piperazine.