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Updated: May 6, 2026

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
Published on: February 24, 2015
Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains
Assaad Nasr El Dine1, Ali Khalaf, Danielle Grée
1Université de Rennes 1, Institut des Sciences Chimiques de Rennes, CNRS UMR 6226, Avenue du Général Leclerc, 35042 Rennes Cedex, France ; Laboratory for Medicinal Chemistry and Natural Products, Lebanese University, Faculty of Sciences (1) and PRASE-EDST, Hadath, Beyrouth, Lebanon.
Abstract:
Starting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated.
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