El Dine AN, Khalaf A, Grée D, Tasseau O, Fares F, Jaber N, Lesot P, Hachem A, Grée R. Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains.
Beilstein J Org Chem 2013;
9:1943-8. [PMID:
24204405 PMCID:
PMC3817575 DOI:
10.3762/bjoc.9.230]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/06/2013] [Indexed: 01/04/2023] Open
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.
Collapse