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∼28% EtCl relative to total functionalized product when using
periodate–chloride. One explanation is that there is a higher
concentration of chloride present in the reaction with period-
ate (1.4 mmol vs. 0.67 mmol). However, even running the
ethane functionalization reaction with 7.7 mmol KIO4 and
0.67 mmol KCl, we still observe ∼23% EtCl (ESI†).
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Previously, we observed ∼1.7 : 1 ratio of iPrTFA to nPrTFA
for propane functionalization when using NH4IO3 and KCl.
For KIO4–KCl, that ratio is increased to ∼2.6 : 1. Likewise,
the ratio of mono- and difunctionalized products for the
iodate system was ∼1.3 : 1, while the ratio is ∼3.4 : 1 for the
periodate reaction described herein.54 Thus, the periodate
system reported herein is more selective for both the mono-
functionalized product and the branched product. However, a
potentially relevant comparison is the ratio of the sum of
iPrTFA and 1,2-difunctionalized product to nPrTFA. If the
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iPrTFA, one would expect these ratios to be similar between 11 A. Caballero and P. J. Perez, Chem. Soc. Rev., 2013, 42, 8809.
iodate and periodate, assuming a similar mechanism was 12 E. Roduner, W. Kaim, B. Sarkar, V. B. Urlacher, J. Pleiss,
operative. Indeed, for both iodine species, the ratio is ∼3.6 : 1
(Table 1).
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In summary, we have demonstrated that the mixture of
KIO4 and KCl in HTFA is an efficient system for the mono- 13 H. Schwarz, Angew. Chem., Int. Ed., 2011, 50, 10096.
functionalization of light alkanes even at low pressures. 14 A. Gunay and K. H. Theopold, Chem. Rev., 2010, 110, 1060.
Yields of functionalized products from methane, ethane 15 A. P. Nelson and S. G. DiMagno, J. Am. Chem. Soc., 2000,
and propane reach over 20%, and in the case of methane at
860 kPa, a 42% yield of MeX is observed. Additionally, compari- 16 P. E. Gormisky and M. C. White, J. Am. Chem. Soc., 2013,
son to our previously reported hydrocarbon functionalization 135, 14052.
using iodate and chloride salts provides evidence that these 17 S. A. Stoian, G. Q. Xue, E. L. Bominaar, L. Que and
two systems operate via a similar pathway.54 By optimizing the
E. Münck, J. Am. Chem. Soc., 2014, 136, 1545.
reaction conditions, a greater yield of MeX is observed for the 18 U. Hintermair, S. W. Sheehan, A. R. Parent, D. H. Ess,
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periodate system reported here than for the iodate system at
200 °C. The high activity observed at 200 °C is important for
D. T. Richens, P. H. Vaccaro, G. W. Brudvig and
R. H. Crabtree, J. Am. Chem. Soc., 2013, 135, 10837.
the development of industrially viable systems, considering 19 W. Liu and J. T. Groves, J. Am. Chem. Soc., 2010, 132, 12847.
the exothermic nature of the reaction and the energy and cost 20 W. Liu and J. T. Groves, Angew. Chem., Int. Ed., 2013, 52,
needed to cool large scale industrial reactions.7 Understanding
6024.
the mechanism of these transformations may allow for the 21 W. Liu, X. Y. Huang, M. J. Cheng, R. J. Nielsen,
development of more active and efficient catalytic systems for W. A. Goddard and J. T. Groves, Science, 2012, 337, 1322.
the conversion of natural gas into liquid fuels. Efforts into elu- 22 Alkane C–H Activation by Single-Site Metal Catalysis,
cidating the mechanism are currently underway in our labora-
tories and will be reported in due course.
This work was solely supported as part of the Center for
Catalytic Hydrocarbon Functionalization, an Energy Frontier
ed. P. J. Perez, Springer, 2012.
23 K. I. Goldberg and A. S. Goldman, Activation and
Functionalization of C–H Bonds, ed. K. I. Goldberg and
A. S. Goldman, American Chemical Society, 2004.
Research Center funded by the U.S. Department of Energy 24 T. B. Gunnoe, in Physical Inorganic Chemistry: Reactions,
(DE-SC0001298). We also acknowledge Dr Matthew E. O’Reilly
Processes, and Applications, ed. A. Bakac, Hoboken, NJ,
(University of Virginia) for performing preliminary reactions
2010.
and Mr Michael S. Webster-Gardiner (University of Virginia) 25 J. S. Owen, J. A. Labinger and J. E. Bercaw, J. Am. Chem.
for helpful discussions.
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