A novel method toward synthesis of sulfonamides and β-arylsulfonyl enamines has been developed via I2/TBHP mediated C-N and C-H bond cleavage of tertiary amines, which features highly selective formation of two different target products depending on the reaction solvent. The experimental results reveal that H2O as the solvent could effectively achieve the C-N bond cleavage to produce sulfonamides due to H2O participating in the reaction process where H2O plays a dual role. Differing from H2O, organic solvents (such as dimethyl sulfoxide) could promote the C-H bond cleavage of tertiary amines to yield β-arylsulfonyl enamines.