Catalyst‐Free S–S Bond Insertion Reaction of a Donor/Acceptor‐Free Carbene by a Radical Process: A Combined Experimental and Computational Study

Abstract

Herein, a donor/acceptor‐free carbene insertion reaction of an S–S bond through a radical process is presented. This catalyst‐free reaction was thermally induced and provided the dithioketal products in moderate to high yields. A mechanism involving radical intermediates was proposed according to the computational study, and these intermediates were verified experimentally and intercepted for the first time by using a cross‐coupling reaction.

Advances in [1,2]-Sigmatropic Rearrangements of Onium Ylides via Carbene Transfer Reactions

“…Further experiments in the presence of TEMPO as a radical-trapping reagent provided further evidence of the participation of radical intermediates in this reaction. 65 A distinct observation was made by Koenigs and coworkers for insertion reactions into Se-Se bonds. In 2019, they reported rhodium-catalyzed formal insertion reactions via carbene transfer of donor/acceptor diazoacetates 53 into the Se-Se bonds of diselenides 317 to yield selenoketals.…”

A Transition‐Metal‐Free and Base‐Mediated Carbene Insertion into Sulfur‐Sulfur and Selenium‐Selenium Bonds: An Easy Access to Thio‐ and Selenoacetals

“…It clearly supports that the reaction does not proceed via deoxygenative thioacetalization. To examine the possibility of whether a sulfur radical (ArS ⋅ ) is involved in the insertion process, a radical trapping experiment was carried out (Scheme , eq 6). The addition of 2 equiv.…”

Copper-Catalyzed Carbene Insertion into the Sulfur–Sulfur Bond of RS–SCF2H/SCF3 under Mild Conditions

“…11 In 2016, Bao, Xu and co-workers reported a catalyst-free, donor/acceptor free carbene insertion into a S-S bond of diaryl disulfide. 12 Crossover experiments as well as DFT calculations indicated that the reaction proceeded through a radical pathway. Shortly after, Arunprasath and Sekar reported that the carbene from N-tosylhydrazone generated in situ in the presence of a base was able to insert into the S-S bond of diaryl disulfide, although the reaction was proposed to proceed via a sulfonium ylide, followed by 1,2-migration or Stevens rearrangement.…”