Scalable Synthesis of Silacyclohexanones and Ready Access to Silicon Building Blocks.

A simple and efficient two-step method for the synthesis of silacyclohexanones starting from (bromoethylsilanes) using TosMIC is presented. The prepared silacyclohexanones were transformed to nine different heterocycles with silicon incorporation. In addition, the developed methodology was used for the synthesis of a sila analogue of the HDAC6 inhibitor tubastatin A.

A route to access imidazol[1,5-a]indole-1,3-diones and pyrrolo[1,2-c]imidazole-1,3-diones.

A novel and practical route to synthesize imidazol[1,5-a]indoles and pyrrolo[1,2-c]imidazoles via N-H functionalization has been developed. Indole-2-carboxylic acid or pyrrole-2-carboxylic acid with diverse aniline groups and carbonyldiimidazole (CDI), in the presence of a base under microwave conditions, resulted in imidazol[1,5-a]indoles and pyrrolo[1,2-c]imidazoles, respectively. The present method is free of work-up and no need for column chromatography.

Brønsted acid-mediated cyclization-dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines.

An efficient and alternative synthetic approach has been developed to prepare various -(arylethyl)piperazine-2,6-diones from 4-benzenesulfonyliminodiacetic acid and primary amines using carbonyldiimidazole in the presence of a catalytic amount of DMAP at ambient temperature. Piperazine-2,6-diones are successfully transformed to pharmaceutically useful pyridopyrazines or pyrazinoisoquinolines and ene-diamides via an imide carbonyl group activation strategy using a Brønsted acid. Subsequent dehydrosulfonylation reactions of the ene-diamides, in a one pot manner, smoothly transformed them to substituted pyrazinones.