Secondary amine-initiated three-component synthesis of 3,4-dihydropyrimidinones and thiones involving alkynes, aldehydes and thiourea/urea

Abstract

The three-component reactions of aldehydes, electron deficient alkynes and ureas/thioureas have been smoothly performed to yield a class of unprecedented 3,4-dihydropyrimidinones and thiones (DHPMs). The reactions are initiated by the key transformation of an enamine-type activation involving the addition of a secondary amine to an alkyne, which enables the subsequent incorporation of aldehydes and ureas/thioureas. This protocol tolerates a broad range of aryl- or alkylaldehydes, N-substituted and unsubstituted ureas/thioureas and alkynes to yield the corresponding DHPMs with specific regioselectivity.

Keywords

• alkynes
• DHPMs
• diversity
• enamine activation
• multicomponent reactions