Visible Light-Induced Sulfonamidation/Cyclization of Internal Alkenes toward Ring-Fused Quinazolinones

<i>N</i>-(3-Methylbut-2-en-1-yl)quinazolin-4(3<i>H</i>)-ones were designed as new building skeletons for the construction of C2-sulfonamidylated pyrrolo-quinazolinones through photocatalytic cascade sulfonamidation/cyclization with <i>N</i>-sulfonylaminopyridinium salts. Meanwhile, C3-sulfonamidylated piperidino-quinazolinones were constructed using <i>N</i>-(4-methylpent-3-en-1-yl)quinazolin-4(3<i>H</i>)-ones as substrates. The significant feature of this methodology lies in the direct installation of sulfonamidyl into the pyrrolo/piperidino core rather than into the side chain.