Study On Copper-Promoted Reductive-Coupling Of Aryl Iodides With1,1,1-Trifluoro-2-iodoethane

The introduction of fluorine atoms into organic molecules can substantially changetheir properties such as metabolic stability and bioavailability because of theirelectronegativity. In recent years, trifluoromethyl group has attracted more attention dueto the functional group’s strong electron-withdrawing property and nice lipophilicity. Asa result, many studies on trifluromethylation of aromatic compounds for synthetizing(2,2,2-trifluoroethyl)arenes have been reported, but few direct methods for theintroduction of the CH2CF3group on the aromatic ring were reported.According to the previous work and literature research, a further research oncopper-promoted2,2,2-trifluoroethylation of arenes using cheap and available reagentCF3CH2I as the source of the CH2CF3group was done by us for the reaction is simpleand non-toxic. For our study, we are surprised to find the copper powder with biggerparticle size will significantly promote the reaction process. So in this paper, we reportan efficient reaction system for the reductive-couping between aryl iodides and1,1,1-trifluoro-2-iodoethane. This reaction is the development of previous work andprivides a new idea for metal-promoted reductive-couping. This reaction can happen ingood yields under mild conditions compared with previous work and tolerates nitro,formyl, ester, ether, carbonyl, sulfonyl and even azo groups.At the same time, we also investigated selectivity of the reaction. We subjected4-bromo-4’-iodo-1,1’-biphenyl to selective reductive-coupling at the C-I site underoptimal conditions, and found an iodo group react in preference to a bromo group. Notonly that, we have also made a research on the application of the reaction in organicsynthesis. A series of obtained (2,2,2-trifluoroethyl) arenes can contain a leaving groupthat may be further functionalized through cross-coupling. Thus, it provides a practicalmethod for the preparation of complex target molecules carrying(2,2,2-trifluoroethyl)phenyl. Finally, we do some research to gain more insight into themechanism of this reaction.We believe that this system compares favorably with previous systems that have beenreported for this reaction.