LETTER
Decarboxylative Trifluoromethylation of Aryliodides
1715
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With the optimal reaction conditions, we turned our atten-
tion to the scope of this transformation (Scheme 2). Both
electron-rich and electron-deficient aryl iodides could
give the expected trifluoromethylation products in good to
excellent yields, such as the isolated yields of trifluoro-
methyl bisphenyl (2p), diaryl ether (2q), and aryl sulfides
(2r) were 90%, 93%, and 95%, respectively. The proce-
dure tolerated a range of functional groups, such as chlo-
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been reported during the preparation of this manuscript, see:
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However, substrates with nitro substituent and electron-
deficient iodoheterocycles did not give good results. We
supposed that the Ullmann homocoupling reaction was
also activated especially for electron-deficient aryl io-
dides under these conditions. Dehalogenation and the bi-
phenyl byproducts were observed as well. For the
substrates with electron-donating groups, 40 mol% cop-
per source and 40 mol% Ag2O were required to achieve
full conversion. The steric hindrance at the phenyl ring
had little effect on this reaction. For example, 2d, 2f, and
2h gave the corresponding products in 70%, 90%, and
87% yields, respectively, showing that this catalytic sys-
tem was not sensitive to the steric effect for trifluoro-
methylation reaction.
In conclusion, we have discovered a general and efficient
method of Cu/Ag2O-catalyzed decarboxylative trifluo-
romethylation reaction of aryl iodides. The functional-
group tolerance and broad substrate scope are the advan-
tages of this process. Our future efforts will be directed to
systematically explore the effects of additives, ligand
modifications, and substrate scope on the reaction.
Supporting Information for this article is available online at
(23) General Procedure for the Preparation of Aryl
Trifluoromethylation Derivatives
Acknowledgment
This work was supported by the National Natural Science Founda-
tion of China (Project No. 20876021, 20923006) and the Education
Department of Liaoning Province (2009S021).
Method A for the Electron-Deficient Aryl Iodides
(Compounds 1a–e,l–n,p–r)
A flame-dried Schlenk test tube with a magnetic stirring bar
was charged with Cu (9.6 mg, 0.15 mmol), Ag2O (34.8 mg,
0.15 mmol), aromatic halides (0.5 mmol), sodium trifluoro-
acetate (272 mg, 2.0 mmol), and DMF (2 mL) under argon.
Method B for Electron-Rich Aryl Iodides (Compounds
1f–k,o)
A flame-dried Schlenk test tube with a magnetic stirring bar
was charged with Cu (12.8 mg, 0.2 mmol), Ag2O (46.4 mg,
0.2 mmol), aromatic halides (0.5 mmol), sodium trifluoro-
acetate (272 mg, 2.0 mmol), and DMF (2 mL) under argon.
After reacting at 130 °C for 15 h, the reaction mixture was
cooled to ambient temperature, and extracted with EtOAc
(3 × 20 mL). The combined organic layers were dried over
anhyd Na2SO4 and concentrated under vacuum. The residue
was purified by column chromatography on silica gel with
an eluent of PE and EtOAc.
References and Notes
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(24) After the reaction mixture was cooled to r.t., the yields of
compounds 2a–f,h,i,l were determined by 19F NMR with
CF3CH2OH (0.5 mmol, 36 mL) as internal standard due to
their low bp; compounds 2a,d,h are also commercial
available.
(5) Dubinina, G. G.; Brennessel, W. W.; Miller, J. L.; Vicic,
D. A. Organometallics 2008, 27, 3933.
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Synlett 2011, No. 12, 1713–1716 © Thieme Stuttgart · New York