Journal of the American Chemical Society
Article
D. P.; Malacria, M.; Fensterbank, L.; Laco
Macromolecules 2010, 43, 2261−2267.
(6) (a) Monot, J.; Solovyev, A.; Bonin-Dubarle, H.; Derat, E.; Curran,
D. P.; Robert, M.; Fensterbank, L.; Malacria, M.; Lacote, E. Angew.
Chem., Int. Ed. 2010, 49, 9166−9169. (b) Braunschweig, H.; Chiu, C.-
W.; Radacki, K.; Kupfer, T. Angew. Chem., Int. Ed. 2010, 49, 2041−
2044.
(7) (a) Wang, Y.; Quillian, B.; Wei, P.; Xie, Y. M.; Wannere, C. S.;
King, R. B.; Schaefer, H. F.; Schleyer, P. v. R.; Robinson, G. H. J. Am.
Chem. Soc. 2008, 130, 3298−3299. (b) Wang, Y.; Quillian, B.; Wei, P.;
Wannere, C. S.; Xie, Y.; King, R. B.; Schaefer, H. F.; Schleyer, P. v. R.;
Robinson, G. H. J. Am. Chem. Soc. 2007, 129, 12412−12413.
(8) (a) Walton, J. C.; Makhlouf Brahmi, M.; Monot, J.; Fensterbank,
̂
te, E.; Lalevee
́
, J.
1971, 93, 3940−3946. (d) Parks, D. J.; Piers, W. E.; Yap, G. P. A.
Organometallics 1998, 17, 5492−5503.
(21) With some cyclic alkenes migrations also occur from one
secondary carbon to another driven by the presence of large, adjacent
branching substituents. See: Hupe, E.; Denisenko, D.; Knochel, P.
Tetrahedron 2003, 59, 9187−9198.
(22) Brown, H. C.; Ravindran, N. Synthesis 1977, 695−697.
(23) Yamaguchi, Y.; Kashiwabara, T.; Ogata, K.; Miura, Y.;
Nakamura, Y.; Kobayashi, K.; Ito, T. Chem. Commun. 2004, 2160−
2161.
(24) With decreased loading (1.7 mol %) of catalyst TrB(C6F5)4 in
C6D5Br, a minor triplet was observed at −25 ppm starting from (E)-3-
hexene and 2 that may be a monoalkylborane, but experiments in
bromobenzene were not pursued due to the greater convenience of
DCM.
(25) 2-Methyl-4-phenylbutene undergoes catalyzed hydroboration
under the usual conditions with 2 and 5% Tf2NH as catalyst,
suggesting that the inhibiting effect of a phenyl substituent is lower for
the terminal alkene compared to the 1,2-disubstituted substrates. This
inhibiting effect may be due to the Lewis basicity of the nearby phenyl
ring. However, we have already identified modified reagents that react
with phenyl-substituted alkenes, and the scope of these reactions is
under study.
(26) In preliminary experiments, 61% conversion was found with the
terminal alkene benzyl 2-allylcyclohexyl ether using 2 and 5% Tf2NH
loading, 3 h at room temperature, but the disubstituted 2-butenyl
analogue of the benzyl ether 20 gave <3% hydroboration product
under these conditions.
́
̂
L.; Malacria, M.; Curran, D. P.; Laco
10312−10321. (b) Walton, J. C.; Makhlouf Brahmi, M.; Fensterbank,
L.; Lacote, E.; Malacria, M.; Chu, Q.; Ueng, S.-H.; Solovyev, A.;
Curran, D. P. J. Am. Chem. Soc. 2010, 132, 2350−2358.
̂
(9) (a) Curran, D. P.; Boussonniere, A.; Geib, S. J.; Lacote, E. Angew.
̂
te, E. J. Am. Chem. Soc. 2011, 133,
̂
̀
Chem., Int. Ed. 2012, 51, 1602−1605. (b) Bissinger, P.; Braunschweig,
H.; Kraft, K.; Kupfer, T. Angew. Chem., Int. Ed. 2011, 50, 4704−4707.
(c) Wang, Y.; Robinson, G. H. Inorg. Chem. 2011, 50, 12326−12337.
(d) Kinjo, R.; Donnadieu, B.; Celik, M. A.; Frenking, G.; Bertrand, G.
Science 2011, 333, 610−613.
(10) (a) Smith, K.; Pelter, A. In Comprehensive Organic Synthesis;
Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, U.K., 1991;
Vol. 8, p 703. (b) Zaidlewicz, M. In Comprehensive Organometallic
Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E., Eds.; Pergamon:
Oxford, U.K., 1982; Vol. 7, pp 143−254.
(11) Staubitz, A.; Robertson, A. P. M.; Sloan, M. E.; Manners, I.
Chem. Rev. 2010, 110, 4023−4078.
(12) (a) Corey, E. J. Angew. Chem., Int. Ed. 2009, 48, 2100−2117.
(b) Piers, W. E.; Bourke, S. C.; Conroy, K. D. Angew. Chem., Int. Ed.
2005, 44, 5016−5036. (B) Hudnall, T. W.; Gabbaï, F. P. J. Am. Chem.
Soc. 2007, 129, 11978−11986.
(13) (a) Kolle, P.; Noth, H. Chem. Rev. 1985, 85, 399−418. (b) De
̈
̈
Vries, T. S.; Prokofjevs, A.; Vedejs, E. Chem. Rev. 2012, in press.
(14) (a) Solovyev, A.; Geib, S. J.; Lacote, E.; Curran, D. P.
̂
Organometallics 2012, 31, 54−56. (b) McArthur, D.; Butts, C. P.;
Lindsay, D. M. Chem. Commun. 2011, 47, 6650−6652. (c) Mansaray,
H. B.; Rowe, A. D. L.; Phillips, N.; Niemeyer, J.; Kelly, M.; Addy, D.
A.; Bates, J. I.; Aldridge, S. Chem. Commun. 2011, 47, 12295−12297.
(d) Matsumoto, T.; Gabbaï, F. P. Organometallics 2009, 28, 4252−
4253. (e) Weber, L.; Dobbert, E.; Stammler, H.-G.; Neumann, B.;
Boese, R.; Blaser, D. Chem. Ber. 1997, 130, 705−710.
̈
́
(15) Ines, B.; Patil, M.; Carreras, J.; Goddard, R.; Thiel, W.; Alcarazo,
M. Angew. Chem., Int. Ed. 2011, 50, 8400−8403.
(16) (a) Shapland, P.; Vedejs, E. J. Org. Chem. 2006, 71, 6666−6667.
(b) Karatjas, A. G.; Vedejs, E. J. Org. Chem. 2008, 73, 9508−9510.
(c) Clay, J. M.; Vedejs, E. J. Am. Chem. Soc. 2005, 127, 5766−5767.
(d) Activation of phosphine or amine boranes using the trityl salt
Ph3CB[C6F5]4 has been demonstrated in hydroborations: De Vries, T.
S. Ph. D. Dissertation, University of Michigan, 2007; highlights are
described in ref 13b, section 8.2. (e) Similar activation methods have
been used to induce aliphatic C−H borylation: Prokofjevs, A.; Vedejs,
E. J. Am. Chem. Soc. 2011, 133, 20056−20059.
(17) Only small hints of HB were observed at 50 °C when a mixture
of (E)-3-hexene and the relatively hindered [1,3-bis(2,6-diisopropyl-
phenyl)imidazol-2-ylidene]borane was treated with 30 mol % Tf2NH.
(18) De Vries, T. S.; Vedejs, E. Organometallics 2007, 26, 3079−
3081.
(19) Kutt, A.; Rodima, T.; Saame, J.; Raamat, E.; Maemets, V.;
̈
̈
Kaljurand, I.; Koppel, I. A.; Garlyauskayte, R. Y.; Yagupolskii, Y. L.;
Yagupolskii, L. M.; Bernhardt, E.; Willner, H.; Leito, I. J. Org. Chem.
2011, 76, 391−395.
(20) (a) Brown, H. C.; Knights, E. F.; Scouten, C. G. J. Am. Chem.
Soc. 1974, 96, 7765−7770. (b) Brown, H. C.; Bhatt, M. V. J. Am.
Chem. Soc. 1966, 88, 1440−1443. (c) For a mechanistic interpretation
of boron migration, see: Rickborn, B.; Wood, S. E. J. Am. Chem. Soc.
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