HIGHLY DIASTEREOSELECTIVE FOUR-COMPONENT SYNTHESIS OF POLYSUBSTITUTED 1,4,5,6-TETRAHYDROPYRIDINES

Abstract

A novel four-component diastereoselective synthesis of polysubstituted tetrahydropyridines is reported. The Michael addition – Mannich reaction – cyclization – dehydration cascade of benzylidenemalononitriles, esters of 3-oxocarboxylic acids, aromatic aldehydes, and ammonium acetate in methanol provides convenient access to 2-substituted alkyl (4SR,6RS)-4,6-diaryl-5,5-dicyano-1,4,5,6-tetrahydropyridine-3-carboxylates with two stereocenters in 66–92% yields. The formation of products was highly stereoselective, with only one diastereomer formed. Ammonium acetate plays dual role acting as a base and as a nitrogen source. Structures of the synthesized compounds were confirmed by 1H, 13C NMR, IR, and mass spectral studies. The formation of single diastereomer was confirmed by singe crystal X-ray diffraction studies.