Photocatalyst-Free Activation of Sulfamoyl Chlorides
for Regioselective Sulfamoyl-Oximation of Alkenes via Hydrogen Atom
Transfer (HAT) and Halogen-Atom Transfer (XAT) Relay Strategy
posted on 2024-03-07, 14:41authored byWei Li, Zhihua Huang, Deliang Zhong, Huaifeng Li
The use of readily available and
diverse sulfamoyl chlorides for
synthesizing sulfonamide compounds presents an intriguing, yet significantly
underexplored strategy. Activating sulfamoyl chlorides via single-electron
reduction poses challenges due to their high reduction potential.
Alternatively, the SO2–Cl bond in sulfamoyl chlorides
could be readily cleaved by XAT. However, the existing methodologies
have been limited to either the use of photocatalyst or the monofunctionalization
of activated alkenes. Here, we report a regioselective sulfamoyl-oximation
of alkenes by involving the activation of sulfamoyl chlorides through
a HAT and XAT relay strategy in a photocatalyst-free way. The key
to this success lies in the dual roles of tert-butyl
nitrite (TBN), which not only serves as the source of oximes but also
acts as the HAT reagent to generate the crucial XAT reactive species.
The exclusion of metal catalysts or photosensitizers for utilizing
light energy renders this protocol versatile and universally applicable
for synthesizing a broad range of structurally diverse oxime-containing
alkyl sulfonamides.