An unprecedented tandem synthesis of fluorescent coumarin-fused pyrimidines via copper-catalyzed cross-dehydrogenative C(sp)-N bond coupling.

An efficient, one-pot Cu-catalyzed tandem synthesis of fluorescent 1-benzyl-2-phenyl-1,2-dihydro-5H-chromeno[4,3-d]pyrimidin-5-ones from 4-chloro-3-formylcoumarin and benzylamines was developed by in situ intramolecular cross-dehydrogenative C(sp3)-N bond formation in moderate-to-good yields under ligand-free ambient conditions. This synthesis was easily scalable, and the generality of the substrates was established. These coumarin-fused pyrimidines exhibited interesting photo-physical properties and high quantum yields, and would be potential candidates for facilitating suitable studies in medicinal chemistry and materials science.