5565-32-2Relevant articles and documents
Silyl Radical-Mediated Activation of Sulfamoyl Chlorides Enables Direct Access to Aliphatic Sulfonamides from Alkenes
Gouverneur, Véronique,Hell, Sandrine M.,Laudadio, Gabriele,Meyer, Claudio F.,Misale, Antonio,No?l, Timothy,Trabanco, Andrés A.,Willis, Michael C.
supporting information, p. 720 - 725 (2020/02/20)
Single electron reduction is more challenging for sulfamoyl chlorides than sulfonyl chlorides. However, sulfamoyl and sulfonyl chlorides can be easily activated by Cl-atom abstraction by a silyl radical with similar rates. This latter mode of activation was therefore selected to access aliphatic sulfonamides, applying a single-step hydrosulfamoylation using inexpensive olefins, tris(trimethylsilyl)silane, and photocatalyst Eosin Y. This late-stage functionalization protocol generates molecules as complex as sulfonamide-containing cyclobutyl-spirooxindoles for direct use in medicinal chemistry.
Allylsilanes in "tin-free" oximation, alkenylation, and allylation of alkyl halides
Rouquet, Guy,Robert, Frederic,Mereau, Raphael,Castet, Frederic,Landais, Yannick
scheme or table, p. 13904 - 13911 (2012/01/15)
Tin-free oximation, vinylation, and allylation of alkyl halides have been developed by using allylsilanes as di-tin surrogates. Initiation of the radical process with a peroxide provides the silyl radical, which can abstract a halogen from the corresponding alkyl halide. The resulting carbon-centered radical then adds to various acceptors, including a sulfonyloxime, a vinylsulfone, and an allylsulfone, leading to formation of the desired products along with the corresponding allylsulfone resulting from the reaction of the PhSO2 radical with the allylsilane precursor. Better results were generally obtained with methallylsilane 1b than with 1a. This observation was rationalized by invoking the higher nucleophilicity of 1b and the faster β-fragmentation of the corresponding β-silyl radical intermediate. Calculation of the energy barrier for the β-fragmentation of a series of β-silyl radicals at the DFT level supported this hypothesis. Finally, a second version of these oximation and vinylation reactions, based on the utilization of 3-tris(trimethylsilyl)silylthiopropene, was devised, affording the desired oximes and olefins in reasonable yields. This strategy allowed the title reaction to be performed under milder conditions (AIBN, benzene, 80°C), as a result of the easier β-fragmentation of the C-S bond as compared with the C-Si bond.
