Essential Multicomponent Reactions II

Diastereoselective Synthesis of 3,4-Dihydropyran-3-carboxamides with in Vitro Anti-inflammatory Activity

“…By means of multicomponent domino reactions (MCDRs), multiple bonds can be formed consecutively in one pot from several building blocks or from an in situ-formed intermediate with a strategically positioned reactive site. − It is well-known that functionalized 1,4-dihydropyridines can readily be prepared in one pot via a four-component reaction of Hantzsch reagents (aldehydes, amines, and two 1,3-dicarbonyl molecules). − Technically, however, treatment of Hantzsch reagents could also result in another structure, 2-amino-3,4-dihydropyran, via nucleophilic attack of enolate to the electron-deficient imine in the final step of cyclization. Considering the above points and our continued interest in the one-pot synthesis of heterocyclic compounds − wherein iodine is used as a Lewis acid catalyst, we designed a five-component Hantzsch-type reaction (Figure ) to construct a novel molecule bearing a 2-amino-3,4-dihydropyran-3-carboxamide core.…”