Phosphomolybdic Acid‐Catalyzed One‐Pot Multicomponent Synthesis of 1,2,5,6‐Tetrahydropyridine Derivatives

We report the synthesis of alkyl 1,2,6‐triaryl‐4‐arylaminopiperidine‐3‐ene‐3‐carboxylates in acceptable yields (42%–71%) and high trans‐diastereoselectivity (69:31 to 100:0) through a one‐pot multicomponent reaction of aromatic aldehydes, aromatic amines, and β‐ketoesters catalyzed by phosphomolybdic acid in methanol at room temperature. The structure and stereochemistry of tetrahydropyridines were confirmed by X‐ray crystallography. This protocol stands out for its operational simplicity, the use of an inexpensive and commercially available heteropolyacid catalyst, low catalyst loading, and purification via simple filtration, resulting in acceptable yields and high diastereoselectivity. Commercially available phosphomolybdic acid‐catalyzed the simple one‐pot multicomponent synthesis of alkyl 1,2,6‐triaryl‐4‐arylaminopiperidine‐3‐ene‐3‐carboxylates in acceptable yields under mild reaction conditions, four new compounds were obtained. X‐ray diffraction analysis of two products confirmed the diastereoselective synthesis of the trans‐diastereomer by forming five sigma bonds and two chiral centers.