Synthesis of fused dihydropyrano(furano)pyridines via [4 + 2]-cycloaddition of 5-alkenoxy substituted oxazoles.

A three-step procedure to access fused pyridines has been developed utilizing inexpensive amino acids and alkenols to form the key oxazole precursors. Yields are good to excellent and provide a rapid and inexpensive route to a range of pharmacologically and biologically valuable fused pyridines with difficult to access substitution patterns.