Expanding the Diversity of Pyridines Through Annulation of Keto and Diketo Compounds

An efficient gold [Au]-catalyzed one-pot synthesis has been developed for the construction of biologically interesting mono- and bipyridines by utilizing the commercially available cyclic ketones and propargylamine in a sealed tube. The formation of bipyridine derivative 21 a indicates that annulation followed by retro-Diels–Alder reaction is occurring with norbornene system. However, keto-derivatives containing bicyclo[2.2.2]octene system 25 indicate that retro-Diels–Alder reaction is not facile. Compounds 32 a and 33 a were subjected to ring opening cross- metathesis to generate diversity and further functionalization of pyridine derivatives.