Michael–Michael Addition Reactions Promoted by Secondary Amine-Thiourea: Stereocontrolled Construction of Barbiturate-Fused Tetrahydropyrano Scaffolds and Pyranocoumarins

Bifunctional secondary amine-thiourea organocatalysts were successfully applied in the stereocontrolled synthesis of barbiturate-fused tetrahydropyrano scaffolds. Compared with typically used tertiary amine-thiourea organocatalysts, the developed catalysts exhibited excellent catalytic performance in the domino Michael–Michael reaction between N, N′-dimethylbarbituric acid and Morita–Baylis–Hillman acetates of nitroalkenes to yield pharmaceutically important heterocycles in good yields with excellent enantioselectivities. Moreover, this catalytic protocol can also be applied to synthesize biologically active pyranocoumarin compounds.