Rongalite as a Sulfone Source: Sulfonylation of para‐Quinone Methides and Alkyl/allyl Halides

Abstract

A one-pot three-component reaction using pquinone methides, rongalite and alkyl/allyl halides has been described. The corresponding unsymmetrical sulfones were obtained in good yields under mild reaction conditions in the absence of any metal, base or any other additive.

Radical Cascade Cyclization of Unactivated Alkene-Tethered Indoles with Aryldiazonium Salt and Sodium Metabisulfite to Access Azo- and Sulfonylated-2,3-Dihyro-1H-pyrrolo[1,2-a]indoles

“…Toward this, we envisioned that the arylsulfonyl radical would be a suitable S-centered radical source to react with 1 under metal- or oxidant-free conditions. In continuation of our recent research interest in introducing the sulfone group in a benign way, we herein report the first arylsulfonyl radical addition to indole N -tethered unactivated olefins followed by cyclization to obtain product type B (Scheme b).…”

Recent Developments in Rongalite Chemistry: A Critical Review

“…(scheme 5). [20] Although in this study, the authors have tried several solvents (e. g. DMSO, DMF, MeCN, EtOH, toluene, dichloromethane) and SO 2 precursors (DABSO, Na 2 S 2 O 5 , rongalite), but rongalite in DMF at room temperature (rt) was found the best choice for this particular transformation. Interestingly, by utilizing this simple yet powerful methodology, they have synthesized a library of unsymmetrical sulfones in moderate to excellent yields.…”

“…To this regard, unsymmetrical sulfones by means of "one-pot three-components" reaction utilizing rongalite, pquinone methides, & alkyl/allyl halides in the absence of any base, metal or other additive under mild condition has successfully been revealed by Kale et al (scheme 5). [20] Although in this study, the authors have tried several solvents (e. g. DMSO, DMF, MeCN, EtOH, toluene, dichloromethane) and SO 2 precursors (DABSO, Na 2 S 2 O 5 , rongalite), but rongalite in DMF at room temperature (rt) was found the best choice for this particular transformation. Interestingly, by utilizing this simple yet powerful methodology, they have synthesized a library of unsymmetrical sulfones in moderate to excellent yields.…”

Synthesis of N-functionalized 2,3-disubstituted benzofurans/naphthofurans from para-quinone methides and isocyanides via the [4 + 1] annulation pathway

“…Only one example leading to naphthofurans was performed (Scheme 1c). 5 c In continuation of our interest in the chemistry of p -QMs, 6 we envisioned that it might be possible to develop a catalytic process for the synthesis of benzo- and naphtho-furans through a [4 + 1] annulation reaction between 2-hydroxy-substituted p -QMs and various alkyl/aryl isocyanides under Lewis acid catalysis (Scheme 1d). 7 The success of this reaction would represent the first example of the synthesis of 2-amino substituted benzo- and naphtho-furan scaffolds starting from p -QMs.…”