Purahong N.Hongthong S.Chotsaeng N.Kuhakarn C.Meesin J.Mahidol University2023-09-152023-09-152023-01-01Synlett (2023)09365214https://repository.li.mahidol.ac.th/handle/123456789/90014The present work describes 1,8-diazabicyclo[5.4.0]-7-undecene (DBU)-promoted self-dimerization of 9-chlorofluorenes and 3-chlorooxindoles for the production of the respective 9,9′-bifluorenylidene and isoindigo derivatives in moderate to good yields (29-97% yield). The reaction readily proceeded under mild and metal-free conditions with short reaction time. A scale-up synthesis (5.0 mmol) of some selected 9,9′-bifluorenylidene derivatives in decent yields highlights the synthetic utility of the reported protocol.ChemistryArticleSCOPUS10.1055/a-2158-79802-s2.0-8516989450414372096