A simple and metal-free direct cyanoisopropylation/arylation of N-arylacrylamides or N-alkyl-N-(arylsulfonyl)acrylamides with AIBN has been developed with cheap and readily available CH₃NO₂ as both the solvent and the oxidant. This reaction provides an efficient approach to cyano-containing oxindoles, which are highly valued synthetic intermediates of biologically active molecules. A series of N-alkyl-N-(arylsulfonyl)acrylamide substrates could be converted into the corresponding oxindoles in good yields and with excellent chemoselectivity via one-pot cyanoisopropylation/aryl migration/desulfonylation and C(sp²)-N bond formation. In contrast to previous reports, the mild conditions together with lack of a need for any metal catalysts and additional oxidants make this protocol very easy to handle and practical.