Three-Component Synthesis of 2,3,5-Triaryl Pyridines

Significance

A palladium-catalyzed, three-component synthesis of 2,3,5-triaryl-substituted pyr­idines is reported. The reaction system was devised incrementally and hence a good understanding of the individual steps has resulted. The first step, Pd-catalyzed coupling of alkenylbromide with morpholine, yields an activated alkene. Palladium catalysis also induces the coupling of the alkenylbromide with the silylimine to form the 2-aza-1,3-buta­diene. Lewis acid catalysis with Yb(OTf)₃ then facilitates a Diels-Alder reaction which, after elimination of morpholine and oxidation, yields the ­pyridine derivative.