Regiocontrolled Synthesis of α-Sulfonylmethyl o-Nitrostyrenes via ZnI2-Mediated Sulfonylation and AgNO2/Pd(PPh3)4-Promoted o-Nitration.

We report herein the AgNO2/Pd(PPh3)4-promoted regiocontrolled o-nitration of α-sulfonylmethylstyrenes in MeNO2 with good yields. The o-nitration process provides a series of sulfonyl o-nitrostyrenes. Substituted α-sulfonylmethylstyrenes were synthesized from ZnI2-mediated sulfonylation of substituted α-methylstyrenes and sodium sulfinates (RSO2Na) in MeCN with good to excellent yields. The structures of the key products were confirmed by X-ray crystallography. A plausible mechanism has been proposed herein.