I2‐Catalyzed/Mediated C−S and C−I Bond Formation: Solvent‐ and Metal‐Free Approach for the Synthesis of β‐Keto Sulfones and Branched Sulfones.

Herein, we report a solvent‐ and transition‐metal‐free, iodine‐catalyzed formation of C−S (sulfone) bonds for the synthesis of β‐keto sulfones using readily accessible methyl ketones and sulfonyl hydrazides. This study also features the α‐functionalization of β‐keto sulfones to synthesize β‐keto thiosulfones and α‐iodo‐β‐keto sulfones via iodine‐catalyzed carbon‐sulfide (C−S) bond formation under solvent‐free conditions and iodine‐mediated C−I bond formation under aqueous conditions, respectively. The analytical studies and control experiments allow insights into a free‐radical coupling strategy. Overall, the presented protocol is operationally simple and scalable, has a broad range of functional group tolerance, and provides access to three functionalized organic scaffolds. [ABSTRACT FROM AUTHOR]