Journal of the American Chemical Society
Communication
(4) Reviews: (a) Seregin, I. V.; Gevorgyan, V. Chem. Soc. Rev. 2007,
36, 1173. (b) Beck, E. M.; Gaunt, M. J. Top. Curr. Chem. 2010, 292,
85. (c) Su, Y.-X.; Sun, L.-P. Mini-Rev. Org. Chem. 2012, 9, 87.
(5) Reviews: (a) McGlacken, G. P.; Bateman, L. M. Chem. Soc. Rev.
2009, 38, 2447. (b) You, S.-L.; Xia, J.-B. Top. Curr. Chem. 2010, 292,
165. (c) Kuhl, N.; Hopkinson, M. N.; Wencel-Delord, J.; Glorius, F.
Angew. Chem., Int. Ed. 2012, 51, 10236.
form and then decay with the concomitant appearance of
product 5. We hypothesize that this intermediate may be a
diaryl PtIV species (4, analogue of III in Scheme 1).25 The
observation of such an intermediate preliminarily suggests that
reductive elimination is the rate-determining step in this Pt-
catalyzed reaction.
We have conducted a number of additional studies to further
probe the reaction mechanism. Rate studies show that both the
C−H arylation of naphthalene and the C−H arylation of
anisole are zero order in Ph2I+. Furthermore, comparison of the
initial rate of naphthalene to that of naphthalene-d8 show a kH/
kD value of 1. An identical result was obtained with anisole/
anisole-d8. These data suggest that neither oxidation nor C−H
cleavage is the rate-determining step of the catalytic reaction.
This is consistent with the proposal (above) of C−C bond-
forming reductive elimination as the rate-determining step.
In summary, this paper demonstrates the first example of
intermolecular PtII/IV-catalyzed direct C−H arylation of simple
arenes. The use of Na2PtCl4 in conjunction with diary-
liodonium oxidants enables arylation of diverse substrates,
with predominantly sterically controlled site selectivity.
Preliminary mechanistic studies suggest that the transformation
proceeds through a PtII/PtIV catalytic cycle and that reductive
elimination may be rate limiting. Compared to analogous Pd-
catalyzed arylation reactions (in which oxidation is rate
limiting), the Pt-catalyzed conditions are effective for a much
broader scope of substrates. Furthermore, the site selectivity of
Pt-catalyzed naphthalene arylation is complementary to that
observed with Pd catalysis. As such, this work represents an
important step toward assembling a set of general, tunable
catalysts for site-selective C−H functionalization of simple
arenes.
(6) Recent examples: (a) Brasche, G.; Garcia-Fortanet, J.; Buchwald,
S. L. Org. Lett. 2008, 10, 2207. (b) Zhang, Y.-H.; Shi, B.-F.; Yu, J.-Q. J.
Am. Chem. Soc. 2009, 131, 5072. (c) Yeung, C. S.; Zhao, X.; Borduas,
N.; Dong, V. M. Chem. Sci. 2010, 1, 331. (d) Izawa, Y.; Stahl, S. S. Adv.
Synth. Catal. 2010, 352, 3223. (e) Campbell, A. N.; Meyer, E. B.; Stahl,
S. S. Chem. Commun. 2011, 47, 10257. (f) Ball, L. T.; Lloyd-Jones, G.
C.; Russell, C. A. Science 2012, 337, 1644. (g) Sanhueza, I. A.; Wagner,
A. M.; Sanford, M. S.; Schoenebeck, F. Chem. Sci. 2013, 4, 2767.
(7) Steric control of selectivity in other C−H bond functionaliza-
tions: (a) Cho, J.-Y.; Iverson, C. N.; Smith, M. R., III. J. Am. Chem. Soc.
2000, 122, 12868. (b) Chotana, G. A.; Rak, M. A.; Smith, M. R., III. J.
Am. Chem. Soc. 2005, 127, 10539. (c) Mkhalid, I. A. I.; Barnard, J. H.;
Marder, T. B.; Murphy, J. M.; Hartwig, J .F. Chem. Rev. 2010, 110, 890.
(d) Wang, X.; Leow, D.; Yu, J.-Q. J. Am. Chem. Soc. 2011, 133, 13864.
(e) Shrestha, R.; Mukherjee, P.; Tan, Y.; Litman, Z. C.; Hartwig, J. F. J.
Am. Chem. Soc. 2013, 135, 8480. (f) Partridge, B. M.; Hartwig, J. F.
Org. Lett. 2013, 15, 140. (g) Robbins, D. W.; Hartwig, J. F. Angew.
Chem., Int. Ed. 2013, 52, 933.
(8) Neufeldt, S. R.; Sanford, M. S. Acc. Chem. Res. 2012, 45, 936.
(9) Li, R.; Jiang, L.; Lu, W. Organometallics 2006, 25, 5973.
(10) Kawai, H.; Kobayashi, Y.; Oi, S.; Inoue, Y. Chem. Commun.
2008, 1464.
(11) Funaki, K.; Kawai, H.; Sato, T.; Oi, S. Chem. Lett. 2011, 40,
1050.
(12) Qin, C.; Lu, W. J. Org. Chem. 2008, 73, 7424.
(13) Kobayashi, O.; Uraguchi, D.; Yamakawa, T. Org. Lett. 2009, 11,
2679.
(14) Park, T.-H.; Hickman, A. J.; Koh, K.; Martin, S.; Wong-Foy, A.
G.; Sanford, M. S.; Matzger, A. J. J. Am. Chem. Soc. 2011, 133, 20138.
(15) Storr, T. E.; Greaney, M. F. Org. Lett. 2013, 15, 1410.
(16) Hickman, A. J.; Sanford, M. S. ACS Catal. 2011, 1, 170.
ASSOCIATED CONTENT
* Supporting Information
■
2−
2−
(17) Standard reduction potential for [PtCl6 2− + 2e− → PtCl4
+
S
2−
2Cl−] = +0.68 V, for [PdCl6 + 2e− → PdCl4 + 2Cl−] = +1.29 V.
Potentials from: Vanysek, P. In CRC Handbook of Chemistry and
Physics, 87th ed.; Lide, D. R., Ed.; CRC Press: Boca Raton, FL, 2006;
pp 8.20−8.29.
Complete experimental and characterization data for all
compounds. This material is available free of charge via the
(18) (a) Shul’pin, G. B.; Rozenberg, L. P.; Shibaeva, R. P.; Shilov, A.
E. Kinet. Katal. 1979, 20, 1570. (b) Shul’pin, G. B. J. Gen. Chem. USSR
1981, 51, 1808. (c) Shibaeva, R. P.; Rozenberg, R. M.; Lobkovskaya, R.
M.; Shilov, A. E.; Shul’pin, G. B. J. Organomet. Chem. 1981, 220, 271.
(d) Shul’pin, G. B.; Nizova, G. V.; Nikitaev, A. T. J. Organomet. Chem.
1984, 276, 115.
AUTHOR INFORMATION
Corresponding Author
■
Notes
The authors declare no competing financial interest.
(19) Intramolecular example: Yamamoto, M.; Matsubara, S. Chem.
Lett. 2007, 36, 172.
ACKNOWLEDGMENTS
■
(20) (a) Byers, P. K.; Canty, A. J.; Honeyman, R. T.; Skelton, B. W.;
White, A. H. J. Organomet. Chem. 1992, 433, 223. (b) Markies, B. A.;
Canty, A. J.; Boersma, J.; van Koten, G. Organometallics 1994, 13,
2053. (c) Crumpton-Bregel, D. M.; Goldberg, K. I. J. Am. Chem. Soc.
2003, 125, 9442. (d) Vedernikov, A. N. Top. Organomet. Chem. 2010,
31, 101.
This material is based upon work supported by the U.S.
Department of Energy [Office of Basic Energy Sciences] DE-
FG02-08ER 15997. A.M.W. and A.J.H. thank the NSF for
graduate fellowships.
(21) For Cu-catalyzed para-selective C−H arylation of electron rich
arenes with diaryliodonium salts, see: Ciana, C.-L.; Phipps, R. J.;
Brandt, J. R.; Meyer, F.-M.; Gaunt, M. J. Angew. Chem., Int. Ed. 2011,
50, 458.
(22) Stark, A. Top. Curr. Chem. 2009, 290, 41.
(23) For entries 8 and 9, the reaction with [Ph2I]TFA provided the
same selectivity.
(24) Kitaigorodskii, A. N.; Nekipelov, V. M.; Nikitaev, A. T.;
Shul’pin, G. B. J. Organomet. Chem. 1984, 275, 295.
(25) This intermediate is formed in low concentration, and attempts
to further characterize it (for example using mass spectrometry) were
unsuccessful.
REFERENCES
■
(1) Reviews: (a) Godula, K.; Sames, D. Science 2006, 312, 67.
(b) Alberico, D.; Scott, M. E.; Lautens, M. Chem. Rev. 2007, 107, 174.
(c) Kakiuchi, F.; Kochi, T. Synthesis 2008, 3013. (d) Chen, X.; Engle,
K. M.; Wang, D.-H.; Yu, J.-Q. Angew. Chem., Int. Ed. 2009, 48, 5094.
(d) Chiusoli, G. P.; Catellani, M.; Costa, M.; Motti, E.; Della Ca’, N.;
Maestri, G. Coord. Chem. Rev. 2010, 254, 456. (e) McMurray, L.;
O’Hara, F.; Gaunt, M. J. Chem. Soc. Rev. 2011, 40, 1885. (f) Yamaguchi,
J.; Yamaguchi, A. D.; Itami, K. Angew. Chem., Int. Ed. 2012, 51, 8960.
(g) Wencel-Delord, J.; Glorius, F. Nat. Chem. 2013, 5, 369.
(2) Lyons, T. W.; Sanford, M. S. Chem. Rev. 2010, 110, 1147.
(3) Yeung, C. S.; Dong, V. M. Chem. Rev. 2011, 111, 1215.
D
dx.doi.org/10.1021/ja408112j | J. Am. Chem. Soc. XXXX, XXX, XXX−XXX