Access to Benzo[a]fluoren‐5‐ones via Photoinduced Cyclization of 1,7‐Enynes Under Photocatalyst and Additive‐Free Conditions

ABSTRACT A visible‐light‐initiated sulfonylation/cyclization of 1,7‐enynes with sulfonyl chlorides under photocatalyst and additive‐free conditions was developed. Furthermore, sunlight serves as a viable light source for facilitating this reaction. This protocol is green and features a broad substrate scope. The mechanistic studies indicated that a sulfonyl radical pathway was involved in this process.