Copper-Catalyzed Radical Sulfonylative Cyclization of o -Vinylanilides with Sulfonyl Chlorides for the Synthesis of Sulfonylated 4 H -Benzo[ d ][1,3]oxazines

][1,3]oxazines under mild conditions. The transformation proceeds at room temperature and exhibits a broad substrate scope and functional-group compatibility, affording structurally diverse products in good to excellent yields. The method is amenable to the late-stage diversification of complex molecules. Preliminary mechanistic studies support a copper-mediated radical cyclization process.