Three-Component Functionalized Dihydropyridine Synthesis via a Formal Inverse Electron-Demand Hetero-Diels–Alder Reaction

Abstract

A mild three-component synthetic approach to versatile 2-amino-1,4-dihydropyridines from terminal alkynes, sulfonyl azides, and <i>N</i>-sulfonyl-1-aza-1,3-butadienes was successfully developed and relied on the in situ generation of metalated ynamide intermediates <b>Ib</b> to achieve a formal inverse electron-demand hetero-Diels–Alder reaction. Experimental results suggest that alkali metal cations (Li⁺ and Cs⁺ ions) might play a critical role to achieve the cycloaddition process