Silica Sulfuric Acid‐Catalyzed Five‐component Efficient Synthesis of Five‐Substituted Tetrahydropyridines

A highly atom-economic one-pot synthesis of five-substituted tetrahydropyridines via a five-component condensation of two equivalents of aromatic aldehyde, two equivalents of aromatic aniline, and one equivalent of β-keto ester catalyzed by silica sulfuric acid is reported. In this reaction, up to five new bonds and one new ring were formed in one pot with water as the only one by-product.