CuSO4-glucose for in situ generation of controlled Cu(I)-Cu(II) bicatalysts: Multicomponent reaction of heterocyclic azine and aldehyde with alkyne, and cycloisomerization toward synthesis of N-fused imidazoles

Article abstract of DOI:10.1021/jo3003024

The catalytic efficiency of mixed Cu(I)-Cu(II) system in situ generated by partial reduction of CuSO₄ with glucose in ethanol (nonanhydrous) under open air has been explored. With this catalysis, the multicomponent cascade reaction of A³-coupling of heterocyclic amidine with aldehyde and alkyne, 5-exo-dig cycloisomerization, and prototropic shift has afforded an efficient and eco-friendly synthesis of therapeutically important versatile N-fused imidazoles. Diverse heterocyclic amidines, several of which are known to be poorly reactive, and aldehydes are compatible in this catalytic process.