NH4OAc-Promoted Domino Route to Hydroxyarylated Unsymmetrical Pyridines Under Neat Conditions

A new metal-oxidant-and solvent-free based eco-friendly domino method for the modular synthesis of a diverse range of medicinally promising hydroxyarylated unsymmetrical pyridines in good to high chemical yields with an excellent regioselectivity has been established. This domino process involves a range of N-sulfonyl ketimines as C,N-binucleophiles, enolizable ketones and aromatic/heteroaromatic aldehydes using ammonium acetate as an ideal promoter under neat conditions which creates new two C-C and one C-N bonds. Notably, the neutral reaction conditions are mild enough to tolerate a range of functionalities and cover a variety of substrates, thus bestowing a powerful avenue to access tri-and tetra-substituted pyridines including carbo-and heterocyclic-fused ones. Interestingly, a practical, scalable and high yielding synthesis of pyridylphenol derivative was successfully accomplished by our unique method.