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

Abstract

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.

Design and Synthesis of Highly Decorated Oxa‐Cage Systems via Olefin Metathesis

“…Thus, the norbornene derivatives 41 and 42, and olefinic compounds 25, 30, 32, 33, 35, 54, and 55 serve as good substrates for ring-opening cross-metathesis (ROCM) as well as cross-metathesis (CM) sequence to expand the application of olefin-metathesis in designing bio-active molecules. [22] Next, oxa-cages 41 and 42 are interesting molecules as they incorporate two bicyclo[2.2.1]heptane systems, and therefore, these compounds were subjected to hydrogenation in the presence of Pd/C under hydrogen atmosphere to obtain the corresponding saturated systems 59 and 60 (Scheme 6).…”

Selectivity: A Goal for Synthetic Economy

“…Here, the bicyclo[2.2.2]octane ring system is less strained as compared to the bicyclo[2.2.1]heptane ring (Scheme 48 ). 63…”