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

Abstract

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.

Red-light-mediated copper-catalyzed photoredox catalysis promotes regioselectivity switch in the difunctionalization of alkenes

“…In addition, product 6 synthesized from 1-bromo-4-vinylbenzene could smoothly give 33 with p -tolylboronic acid via Suzuki-coupling reaction (Fig. 4b ) 72 . Due to the superior light penetration of red light, it became feasible to directly conduct the upscaling of the reaction within a batch reaction system 5 .…”