The first reverse regioselective intermolecular annulation of aryl substituted 2-acetylenic ketones with O-substituted N-hydroxybenzamides or acrylamides followed by tandem cyclization via ruthenium-catalyzed C–H activation, is reported.

The total synthesis of highly potent and scarcely available marine natural product (−)-jahanyne was attempted resulting in a solution-phase synthesis of pruned versions with comparable activity. A simple and facile synthetic route was employed for the preparation of pruned congeners and would be scalable. The lipophilic tail of the natural product was synthesized from R-(+)-citronellol, utilizing easily available chemicals. All the synthesized compounds were screened for apoptotic activity against a panel of cell lines. These compounds depicted marked binding to B cell lymphoma 2 till 50 °C in cellular thermal shift analysis.

The three-component Povarov reaction is efficiently utilized for construction of the pentacyclic framework of complex Melodinus alkaloids, which is amenable to expansion to other complex natural products. The key steps were Povarov reaction, one-pot reductive cyclization, and ring-closing metathesis (RCM) reaction.

Benzyne insertion to build the privileged scaffold of a [6.8.6]-tricyclic framework on polycyclic and sp 3 -rich natural products has been developed. The formation of the [6.8.6]-tricyclic ring system is solvent dependent.

A high yielding metal-catalysed Conia-ene reaction of 2-acetylenic ketones for the synthesis of bicyclo[3.n.1]alkenes has been developed. This simple and efficient 6-endo-dig-cyclization protocol enables the synthesis of a wide variety of bicyclic systems, present in many natural products.