Allylic C–S Bond Construction through Metal-Free Direct Nitroalkene Sulfonation

A metal-free, open-flask
protocol was developed for the preparation
of allylic sulfones through direct condensation of sodium arylsulfinates
and β,β-disubstituted nitroalkenes. The key step of this
process was the Lewis base-promoted equilibrium between nitroalkenes
and allylic nitro compounds. Through this process, the readily available
conjugated nitroalkenes can be easily converted into allylic nitro
compounds, which contain more reactive CC bonds toward the
sulfonyl radical addition. As a result, allylic sulfones were prepared
in excellent yields with a broad substrate scope under mild conditions.