ORGANIC
LETTERS
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Vol. XX, No. XX
000–000
Copper-Catalyzed Oxidative Heck
Reactions between Alkyltrifluoroborates
and Vinyl Arenes
Timothy W. Liwosz and Sherry R. Chemler*
Department of Chemistry, The State University of New York at Buffalo, Buffalo,
New York 14260, United States
Received May 1, 2013
ABSTRACT
We report herein that potassium alkyltrifluoroborates can be utilized in oxidative Heck-type reactions with vinyl arenes. The reaction is catalyzed by a
Cu(OTf)2/1,10-phenanthroline with MnO2 as the stoichiometric oxidant. In addition to the alkyl Heck, amination, esterification, and dimerization reactions
of alkyltrifluoroborates are demonstrated under analogous reaction conditions. Evidence for an alkyl radical intermediate is presented.
CarbonÀcarbon bond formation via alkene CÀH func-
tionalization is a direct and atom-economical method
for the synthesis of more highly substituted alkenes and
analogues thereof.1 The MizorokiÀHeckreaction2 enables
the cross-coupling of aryl and vinyl halides with alkenes.
Although Heck reactions with alkyl halides present a
challenge due to their potential to undergo β-hydride eli-
mination under palladium catalysis, a number of methods
that enable the use of alkyl halides in Heck-type reactions
have recently appeared.3
The oxidative Heck reaction between organometallic
compounds and alkenes is a halide-free alternative to the
MizorokiÀHeck reaction.2i In recent years, aryl and vi-
nylboronates have emerged as generally useful reagents for
the oxidative Heck reaction of alkenes2jÀm and related
arene CÀH functionalizations.4 To date, however, no oxi-
dative alkyl-Heck-type reactions using alkylborates have
been reported, likely due to the complicating β-hydride
(1) Recent examples: (a) Ilies, L.; Asako, S.; Nakamura, E. J. Am.
Chem. Soc. 2011, 133, 7672. (b) Schomaker, J. M.; Boyd, W. C.; Stewart,
I. C.; Toste, F. D.; Bergman, R. G. J. Am. Chem. Soc. 2008, 130, 3777.
(c) Tsai, A. S.; Brasse, M.; Bergman, R. G.; Ellman, J. A. Org. Lett. 2011,
13, 540. (d) Rakshit, S.; Grohmann, C.; Besset, T.; Glorius, F. J. Am.
Chem. Soc. 2011, 133, 2350. (e) Shi, B.-F.; Zhang, Y.-H.; Lam, J. K.;
Wang, D.-H.; Yu, J.-Q. J. Am. Chem. Soc. 2010, 132, 460. (f) Hatamoto,
Y.; Sakaguchi, S.; Ishii, Y. Org. Lett. 2004, 6, 4623. (g) Xu, Y.-H.; Lu, J.;
Loh, T.-P. J. Am. Chem. Soc. 2009, 131, 1372. (h) Yu, H.; Jin, W.; Sun,
C.; Chen, J.; Du, W.; He, S.; Yu, Z. Angew. Chem., Int. Ed. 2010, 49,
5792. (i) Lee, D. H.; Kwon, K. H.; Yi, C. S. Science 2011, 333, 1613.
(2) Selected reviews: (a) The MizorokiÀHeck Reaction; Oestreich, M.,
Ed.; John Wiley & Sons: West Sussex, UK, 2009. (b) Heck, R. F. Acc. Chem.
Res. 1979, 12, 146. (c) de Meijere, A.; Meyer, F. E. Angew. Chem., Int.
Ed. Engl. 1994, 33, 2379. (d) Beletskaya, I. P.; Cheprakov, A. V. Chem.
Rev. 2000, 100, 3009. Cu-catalyzed Heck-type reactions: (e) Iyer, S.;
Ramesh, C.; Sarkar, A.; Wadgaonkar, P. P. Tetrahedron Lett. 1997, 38,
8113. (f) Li, J.-H.; Wang, D.-P.; Xie, Y.-X. Tetrahedron Lett. 2005, 46,
4941. (g) Peng, Y.; Chen, J.; Liu, M.; Gao, W.; Wu, H. Synthesis 2011,
213. (h) Phipps, R. J.; McMurray, L.; Ritter, S.; Duong, H. A.; Gaunt,
M. J. J. Am. Chem. Soc. 2012, 134, 10773. (i) Review of oxidative Heck
reactions: Karimi, B.; Behzadnia, H.; Elhamifar, D.; Akhavan, P. F.;
Esfahani, F. K.; Zamani, A. Synthesis 2010, 1399. Oxidative Heck
reaction using potassium aryltrifluoroborates: (j) Martinez, R. M.; Voica,
F.; Genet, J.-P.; Darses, S. Org. Lett. 2007, 9, 3213. (k) Savmarker, J.;
Lindh, J.; Nilsson, P.; Sjoberg, P. J. R.; Larhed, M. ChemistryOpen 2012,
1, 140. (l) Heck reaction with arylboronic acids and styrenes: Lautens,
M.; Roy, A.; Fukuoka, K.; Fagnou, K.; Martin-Matute, B. J. Am.
Chem. Soc. 2001, 123, 5358. (m) Amengual, R.; Michelet, V.; Genet, J.-P.
Tetrahedron Lett. 2002, 43, 5905.
(3) Recent examples: (a) Kreis, L. M.; Krautwald, S.; Pfeiffer, N.;
Martin, R. E.; Carreira, E. M. Org. Lett. 2013, 15, 1634. (b) Firmansjah,
L.; Fu, G. C. J. Am. Chem. Soc. 2007, 129, 11340. (c) Bloome, K. S.;
McMahen, R. L.; Alexanian, E. J. J. Am. Chem. Soc. 2011, 133, 20146.
(d) Stowers, K. J.; Fortner, K. C.; Sanford, M. S. J. Am. Chem. Soc.
2011, 133, 6541. (e) Weiss, M. E.; Kreis, L. M.; Lauber, A.; Carreira,
E. M. Angew. Chem., Int. Ed. 2011, 50, 11125.
(4) Arylboron reagents: (a) Kakiuchi, F.; Kan, S.; Igi, K.; Chatani,
N.; Murai, S. J. Am. Chem. Soc. 2003, 125, 1698. (b) Giri, R.; Maugel,
N.; Li, J.-J.; Wang, D.-H.; Breazzano, S. P.; Saunders, L. B.; Yu, J.-Q.
J. Am. Chem. Soc. 2007, 129, 3510. (c) Vogler, T.; Studer, A. Org. Lett.
2008, 10, 129. (d) Pouliot, M.; Renaud, P.; Schenk, K.; Studer, A.;
Vogler, T. Angew. Chem., Int. Ed. 2009, 48, 6037. (e) Pastine, S. J.;
Gribkov, D. V.; Sames, D. J. Am. Chem. Soc. 2006, 128, 14220. (f) Shi,
Z.; Li, B.; Wan, X.; Chang, J.; Fang, Z.; Cao, B.; Qin, C.; Wang, Y.
Angew. Chem., Int. Ed. 2007, 46, 5554–5558. Alkylboron reagents in
CÀH arylation of arenes: (g) Chen, X.; Goodhue, C. E.; Yu, J.-Q. J. Am.
Chem. Soc. 2006, 128, 12634.
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10.1021/ol401220b
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