Jamshidi, ElmiraRajai-Daryasarei, SaidehStranger, RobertAriafard, AlirezaRominger, FrankBalalaie, Saeed2025-12-242025-12-240947-6539PubMed:40192152WOS:001500832800001ORCID:/0000-0003-2383-6380/work/198388124https://hdl.handle.net/1885/7337970881-Indanone derivatives are efficiently synthesized via a radical cyclization reaction of 1,6-enynes, using TBHP as both oxidant and reactant, in the presence of Cu(I) as the catalyst and 4-methyl benzoic acid as the cocatalyst. Notably, in the absence of 4-methyl benzoic acid, the reaction undergoes a dramatic shift in product selectivity, yielding 1H‑cyclopropa[b]naphthalene-2,7-diones exclusively under the same conditions, with Cu(I) acting as the sole catalyst. This transformation offers key advantages, including operational simplicity, cost-effective and readily available materials, scalability to gram quantities, and compatibility with a wide range of functional groups. Mechanistic studies and DFT calculations confirmed that the reaction proceeds through a radical pathway, highlighting the pivotal role of 4-methylbenzoic acid as the cocatalyst in altering product selectivity.The authors gratefully acknowledge Iran National Science Foundation (INSF, grant no 99029802). Saeed Balalaie thanks the Alexander von Humboldt Foundation for the research fellowship.10en© 2025 The Author(s)1,6-Enynes1-Indanones4-Methyl benzoic acidCopper(I) CatalysisRadical cyclization2025-06-2310.1002/chem.202501015105007543975