Iron‐Catalyzed Direct C(sp ³ )–H Sulfonylmethylation of Benzofused Ketones with DMA as a Methylene Source

Abstract An efficient iron‐catalyzed C─H bond functionalization strategy has been developed for the direct sulfonylmethylation of benzofused ketones. This three‐component reaction employs sodium sulfinates as the sulfonyl source and dimethylacetamide (DMA) as a versatile one‐carbon synthon, enabling concurrent construction of C─C and C─S bonds. The protocol demonstrates broad functional group tolerance and proceeds under oxidative conditions using FeCl 3 and K 2 S 2 O₈. A variety of α‐tetralones, 1‐indanones, and related substrates were transformed into the corresponding α‐sulfonylmethylated derivatives in moderate to good yields. Mechanistic studies suggest a radical pathway involving a key 2‐methylidenecycloalkan‐1‐one intermediate, offering a practical and step‐economical route to sulfone‐containing scaffolds.