Journal of the American Chemical Society
ARTICLE
’ CONCLUSION
(8) Devasagayaraj, A.; Studemann, T.; Knochel, P. Angew. Chem., Int.
Ed. 1995, 34, 2723–2725.
We describe here a structureꢀactivity study for Ni-catalyzed
alkylꢀalkyl Kumada coupling. A large number of Ni(II) com-
plexes with tridentate (Lockamine) and bidentate (Pengamine)
mixed amino-amide ligands were prepared and structurally
characterized. The complexes of the bidentate ligands span a
wide range of coordination numbers, geometries, and spin states.
The rich coordination chemistry of Ni with these bidentate
ligands points to the difficulty in identifying catalytic active
species in many Ni catalyzed cross coupling reactions, where
the catalysts are mixtures of Ni salts and ligands. Such a problem
can be alleviated by using preformed and well-defined coordina-
tion compounds as catalysts.
(9) Sherry, B. D.; Furstner, A. Acc. Chem. Res. 2008, 41, 1500–1511.
(10) Czaplik, W. M.; Mayer, M.; Cvengros, J.; Jacobi von Wangelin,
A. Chemsuschem 2009, 2, 396–417.
(11) Hu, X. L. Chimia 2010, 64, 231–234.
(12) Kantchev, E. A. B.; O’Brien, C. J.; Organ, M. G. Aldrichim. Acta
2006, 39, 97–111.
(13) Giovannini, R.; Studemann, T.; Dussin, G.; Knochel, P. Angew.
Chem., Int. Ed. 1998, 37, 2387–2390.
(14) Giovannini, R.; Studemann, T.; Devasagayaraj, A.; Dussin, G.;
Knochel, P. J. Org. Chem. 1999, 64, 3544–3553.
(15) Jensen, A. E.; Knochel, P. J. Org. Chem. 2002, 67, 79–85.
(16) Terao, J.; Watanabe, H.; Ikumi, A.; Kuniyasu, H.; Kambe, N.
J. Am. Chem. Soc. 2002, 124, 4222–4223.
Compared to the previously reported pincer complex,
[(MeN2N)NiCl] (1), the newly prepared Ni complexes with
the bidentate Pengamine ligands are better catalysts for the
coupling of secondary alkyl halides, as long as they contain one
transmetalation site. Four-coordinate compounds are more
efficient than five-coordinate compounds. Coordination geome-
try and spin state of the precatalysts seem to have little influence.
For Kumada coupling of secondary alkyl halides, two excellent
catalysts have been developed. Tetrahedral complex [(HNN)Ni-
(PPh3)Cl] (20) is the best catalyst for coupling of bulky acyclic
secondary alkyl iodides, with yields of 46ꢀ65%. Square-planar
complex [(HNN)Ni(2,4-lutidine)Cl] (23) is the best catalyst for
coupling of cyclic and less bulky acyclic secondary alkyl iodides and
bromides. A wide scope has been achieved using this catalyst, with
typical yields of 60ꢀ87%. The origin of the efficiency was thor-
oughly probed and was related to the dissociation of the PPh3 and
2,4-lutidine ligands during catalysis to form 3-coordinate active
species. To the best of our knowledge, these two complexes are the
most efficient catalysts for alkylꢀalkyl Kumada coupling of non-
activated secondary alkyl halides.
(17) Terao, J.; Todo, H.; Begum, S. A.; Kuniyasu, H.; Kambe, N.
Angew. Chem., Int. Ed. 2007, 46, 2086–2089.
(18) Netherton, M. R.; Dai, C. Y.; Neuschutz, K.; Fu, G. C. J. Am.
Chem. Soc. 2001, 123, 10099–10100.
(19) Kirchhoff, J. H.; Dai, C. Y.; Fu, G. C. Angew. Chem., Int. Ed.
2002, 41, 1945–1947.
(20) Netherton, M. R.; Fu, G. C. Angew. Chem., Int. Ed. 2002,
41, 3910–3912.
(21) Zhou, J. R.; Fu, G. C. J. Am. Chem. Soc. 2003, 125, 14726–14727.
(22) Zhou, J. R.; Fu, G. C. J. Am. Chem. Soc. 2003, 125, 12527–12530.
(23) Zhou, J.; Fu, G. C. J. Am. Chem. Soc. 2004, 126, 1340–1341.
(24) Saito, B.; Fu, G. C. J. Am. Chem. Soc. 2007, 129, 9602–9603.
(25) Saito, B.; Fu, G. C. J. Am. Chem. Soc. 2008, 130, 6694–6695.
(26) Lu, Z.; Fu, G. C. Angew. Chem., Int. Ed. 2010, 49, 6676–6678.
(27) Owston, N. A.; Fu, G. C. J. Am. Chem. Soc. 2010, 132,
11908–11909.
(28) Jones, G. D.; Martin, J. L.; McFarland, C.; Allen, O. R.; Hall,
R. E.; Haley, A. D.; Brandon, R. J.; Konovalova, T.; Desrochers, P. J.;
Pulay, P.; Vicic, D. A. J. Am. Chem. Soc. 2006, 128, 13175–13183.
(29) Anderson, T. J.; Jones, G. D.; Vicic, D. A. J. Am. Chem. Soc.
2004, 126, 8100–8101.
(30) Jones, G. D.; McFarland, C.; Anderson, T. J.; Vicic, D. A. Chem.
Commun. 2005, 4211–4213.
(31) Phapale, V. B.; Bunuel, E.; Garcia-Iglesias, M.; Cardenas, D. J.
Angew. Chem., Int. Ed. 2007, 46, 8790–8795.
’ ASSOCIATED CONTENT
(32) Prinsell, M. R.; Everson, D. A.; Weix, D. J. Chem. Commun.
2010, 46, 5743–5745.
(33) Vechorkin, O.; Csok, Z.; Scopelliti, R.; Hu, X. L. Chem.—Eur. J.
2009, 15, 3889–3899.
(34) Vechorkin, O.; Hu, X. L. Angew. Chem., Int. Ed. 2009,
48, 2937–2940.
(35) Donkervoort, J. G.; Vicario, J. L.; Jastrzebski, J.; Gossage, R. A.;
Cahiez, G.; van Koten, G. J. Organomet. Chem. 1998, 558, 61–69.
(36) Cahiez, G.; Chaboche, C.; Jezequel, M. Tetrahedron 2000,
56, 2733–2737.
S
Supporting Information. Experimental and crystallo-
b
graphic details, preparation procedures for substrates, detailed
coupling procedures, all crystallographic files (cif). This material is
’ AUTHOR INFORMATION
Corresponding Author
xile.hu@epfl.ch
(37) Cahiez, G.; Chaboche, C.; Duplais, C.; Giulliani, A.; Moyeux, A.
Adv. Synth. Catal. 2008, 350, 1484–1488.
(38) Tsuji, T.; Yorimitsu, H.; Oshima, K. Angew. Chem., Int. Ed.
2002, 41, 4137–4139.
(39) Hadei, N.; Kantchev, E. A. B.; O’Brien, C. J.; Organ, M. G. Org.
Lett. 2005, 7, 3805–3807.
’ ACKNOWLEDGMENT
This work is supported by the EPFL and the Swiss National
Science Foundation (Project No. 200021_126498).
(40) Valente, C.; Baglione, S.; Candito, D.; O’Brien, C. J.; Organ,
M. G. Chem. Commun. 2008, 735–737.
’ REFERENCES
(1) Netherton, M. R.; Fu, G. C. Adv. Synth. Catal. 2004, 346,
1525–1532.
(2) Frisch, A. C.; Beller, M. Angew. Chem., Int. Ed. 2005, 44, 674–688.
(3) Rudolph, A.; Lautens, M. Angew. Chem., Int. Ed. 2009,
48, 2656–2670.
(41) Nasielski, J.; Hadei, N.; Achonduh, G.; Kantchev, E. A. B.; O’Brien,
C. J.; Lough, A.; Organ, M. G. Chem.—Eur. J. 2010, 16, 10844–10853.
(42) Fischer, C.; Fu, G. C. J. Am. Chem. Soc. 2005, 127, 4594–4595.
(43) Smith, S. W.; Fu, G. C. J. Am. Chem. Soc. 2008, 130,
12645–12647.
(44) Son, S.; Fu, G. C. J. Am. Chem. Soc. 2008, 130, 2756–2757.
(45) Lundin, P. M.; Esquivias, J.; Fu, G. C. Angew. Chem., Int. Ed.
2009, 48, 154–156.
(46) Dai, X.; Strotman, N. A.; Fu, G. C. J. Am. Chem. Soc. 2008,
130, 3302–3303.
(4) Terao, J.; Kambe, N. Acc. Chem. Res. 2008, 41, 1545–1554.
(5) Cardenas, D. J. Angew. Chem., Int. Ed. 2003, 42, 384–387.
(6) Glorius, F. Angew. Chem., Int. Ed. 2008, 47, 8347–8349.
(7) Ishiyama, T.; Abe, S.; Miyaura, N.; Suzuki, A. Chem. Lett.
1992, 691–694.
7094
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