Access to Benzoafluoren‐5‐ones via Photoinduced Cyclization of 1,7‐Enynes Under Photocatalyst and Additive‐Free Conditions

Key Points

• The aim is to develop a visible-light-induced cyclization process for 1,7-enynes without photocatalysts or additives.
• Developed a visible-light-initiated sulfonylation/cyclization of 1,7-enynes.
• Used sulfonyl chlorides as reactants.
• Sunlight was utilized as a light source to facilitate the reaction.
• Investigated the mechanism to confirm the involvement of a sulfonyl radical pathway.
• Successfully synthesized benzo[a]fluoren-5-ones via the photoinduced method.
• Demonstrated a broad substrate scope with the reaction conditions.
• Confirmed the green nature of the method due to the absence of photocatalysts and additives.