Organometallics
Article
A 3.8 mL solution of 6a (0.09 g, 0.25 mmol) in benzene was added
dropwise to the vial. The reaction mixture was stirred at ambient
temperature for 5 h. The resulting precipitate was subsequently filtered
and concentrated under vacuum to give 0.074 g of 9a (53%) as an
of 54/46. All non-hydrogen atoms were refined with anisotropic
displacement parameters. All hydrogen atoms were treated as idealized
contributions. Scattering factors and anomalous dispersion coefficients
are contained in various versions of the SHELXTL program library (G.
M. Sheldrick) or the Olex2 program.21
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orange solid. H NMR (400 MHz, CDCl3): δ 7.36−7.31 (m, 2H),
7.14−6.96 (m, 6H), 6.35−6.28 (m, 1H), 6.06−5.99 (m, 1H), 3.27 (s,
3H), 3.14 (s, 3H), 1.72 (t, J = 6.4, 6H), 1.55 (d, J = 7.0, 3H), 1.48 (d, J
ASSOCIATED CONTENT
* Supporting Information
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= 6.8, 3H). 13C NMR (100 MHz, CDCl3): δ 185.7 (d, JCRh = 56.8,
S
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RhCO), 185.4 (d, JCRh = 78.1, RhCO), 159.9, 158.5, 134.3, 133.8,
Text, figures, tables, and CIF files giving additional detailed
experimental procedures, characterization data for new
compounds, and crystallographic data. This material is available
131.7, 131.2, 122.3, 122.0, 121.9, 121.7, 111.3, 111.1, 108.7, 107.9, 63.7
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(d, JCRh = 26.5, CRh), 50.9, 50.0, 32.8, 32.5, 21.1, 20.5, 19.8, 19.2.
HR-MS (FAB): calcd for [C25H28ClN4O2Rh + H]+ 555.1034. found
555.1036; IR (CH2Cl2): ν 2051.6, 1976.0 cm−1.
Preparation of [RhCl(CO)2(6b)] (9b).4 In a 20 mL vial was placed
[Rh(CO)2Cl]2 (0.095g, 0.25 mmol) in anhydrous benzene (3 mL). A
solution of 6b (0.22 g, 0.5 mmol) in benzene was added dropwise and
was stirred at ambient temperature for 2 h. The reaction mixture was
passed through Celite, and the filtrate solution was concentrated under
vacuum. The crude product was washed with cold ether and then
concentrated under vacuum to give 0.267 g of 9b (84%) as an orange
AUTHOR INFORMATION
Corresponding Author
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Author Contributions
The manuscript was written through contributions of all
authors. All authors have given approval to the final version of
the manuscript.
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solid. H NMR (400 MHz, C6D6): δ 6.98−6.89 (m, 4H), 6.69 (t, J =
12.2, 1H), 6.51(d, J = 7.6 1H), 6.40 (d, J = 7.4, 1H), 6.15 (t, J = 12.4,
1H), 2.94−2.91 (m, 1H), 2.68 (s, 3H), 2.58−2.55 (m, 1H), 2.31 (s,
3H), 2.13−2.06 (m, 2H), 2.05−1.87 (m, 4H), 1.88−1.65 (m, 8H),
1.64−1.55 (m, 2H), 1.14−1.00 (m, 2H). 13C NMR (100 MHz, C6D6):
δ 187.8, 187.3, 187.2, 186.5, 160.8, 158.4, 134.9, 134.1, 133.1, 132.2,
122.8, 122.31, 122.26, 121.8, 112.1, 111.7, 109.3, 108.1, 64.7, 64.4,
59.3, 58.1, 32.5, 32.1, 30.9, 30.3, 30.1, 26.9, 26.6, 26.4, 26.3, 26.2. IR
(CH2Cl2): ν 2051.0, 1975.0 cm−1.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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This work was financially supported by the National Science
Council of Taiwan (NSC-101-2628-M-001-002-MY3 grant)
and Academia Sinica Funding. We also thank Dr. Mei-Chin
Tseng for generous technical support for use of the Mass
Analysis facility.
Preparation of [PdCl(C3H5)(6a)] (10). In a 20 mL vial was placed
[PdCl(C3H5)]2 (0.09 g, 0.25 mmol) in anhydrous THF (5 mL). A
solution of 6a (0.18 g, 0.50 mmol) in THF (7.5 mL) was added
dropwise, and the reaction mixture was stirred at ambient temperature
for 3 h. The resulting precipitate was subsequently filtered and
concentrated in vacuo to give 0.160 g of 10 (51%) as an orange solid.
1H NMR (400 MHz, CDCl3): major product, δ 7.27−6.85 (m, 8H),
6.28−6.22 (m, 1H), 5.99−5.93 (m, 1H), 5.25−5.12 (m, 1H), 4.09−
4.06 (m, 1H), 3.36−3.03 (m, 8H), 2.16 (d, J = 11.5, 1H), 1.75−1.45
(m, 12H); minor product, δ 7.27−6.85 (m, 8H), 6.55−6.49 (m, 1H),
5.64−5.58 (m, 1H), 5.25−5.12 (m, 1H), 4.09−4.06 (m, 1H), 3.36−
3.03 (m, 8H), 2.24 (d, J = 11.6, 1H), 1.75−1.45 (m, 12H). 13C NMR
(100 MHz, CDCl3) δ 157.9, 157.1, 156.5, 155.5, 134.4, 134.1, 132.0,
131.3, 121.8, 121.5, 121.2, 120.9, 110.9, 110.4, 110.3, 110.1, 108.2,
107.9, 107.4, 107.0, 69.8, 69.7, 62.6, 62.2, 49.2, 48.8, 48.5, 47.4, 47.0,
32.4, 32.1, 20.8, 20.4, 20.2, 19.6, 19.2.
X-ray Crystallography Studies. In the crystallographic studies
for 4a−c, 5a, 6a, 7, 9a,b, and 10, crystals were mounted using viscous
oil onto glass fibers and cooled to the data collection temperatures.
Data were collected on a Bruker-AXS APEX CCD diffractometer with
graphite-monochromated Mo Kα radiation (λ = 0.71073 Å). Unit cell
parameters were obtained from 60 data frames, 0.3° ω, from three
different sections of the Ewald sphere. The systematic absences are
uniquely consistent for the reported spacegroups for 4a, 5a, 7, 9a,b,
and 10. No symmetry higher than triclinic was observed for 4b,c, and
solution in the centrosymmetric option yielded chemically reasonable
and computationally stable results. The unit-cell parameters and
systematic absences are consistent for Aba2 (space group No. 39) and
Abmm [Cmmb] (Sspace group No. 67) for 6a. The presence of a
molecular 2-fold and Z = 4 was consistent with Aba2 for 6a; however,
the absence of heavy atoms did not allow for significant Flack
parameter refinements. The data sets were treated with SADABS
absorption corrections on the basis of redundant multiscan data.20 The
structures were solved using direct methods and refined with full-
matrix least-squares procedures on F2. Two symmetry unique but
chemically equivalent molecules were found in the asymmetric unit for
4b. Solvent molecules were located cocrystallized in 4c (CH3CN), 5a
(CHCl3), 9a (THF), 9b (toluene), and 10 (CH2Cl2). The molecule is
located at a 2-fold in 6a with the isopropyl group disordered by
pyramidal inversion at the adjacent amine N atom such that the
tertiary C atom is in two positions with a refined site occupancy ratio
REFERENCES
■
(1) (a) Igau, A.; Grutzmacher, H.; Baceiredo, A.; Bertrand, G. J. Am.
Chem. Soc. 1988, 110, 6463−6466. (b) Igau, A.; Baceiredo, A.;
Trinquier, G.; Bertrand, G. Angew. Chem., Int. Ed. 1989, 28, 621−622.
(c) Arduengo, A. J.; Harlow, R. L.; Kline, M. J. Am. Chem. Soc. 1991,
113, 361−363. (d) Arduengo, A. J.; Dias, H. V. R.; Harlow, R. L.;
Kline, M. J. Am. Chem. Soc. 1992, 114, 5530−5534.
(2) (a) Herrmann, W. A. Angew. Chem., Int. Ed. 2002, 41, 1290−
1309. (b) Hahn, F. E.; Jahnke, M. C. Angew. Chem., Int. Ed. 2008, 47,
́
́
3122−3172. (c) Dıez-Gonzalez, S.; Marion, N.; Nolan, S. P. Chem.
Rev. 2009, 109, 3612−3676. (d) Enders, D.; Niemeier, O.; Henseler,
A. Chem. Rev. 2007, 107, 5606−5655.
(3) Selected Reviews on stable carbenes: (a) Droge, T.; Glorius, F.
̈
Angew. Chem., Int. Ed. 2010, 49, 6940−6952. (b) Melaimi, M.;
Soleilhavoup, M.; Bertrand, G. Angew. Chem., Int. Ed. 2010, 49, 8810−
8849. (c) Martin, D.; Soleilhavoup, M.; Bertrand, G. Chem. Sci. 2011,
2, 389−399. (d) Vignolle, J.; Cattoen, X.; Bourissou, D. Chem. Rev.
̈
2009, 109, 3333−3384. (e) Martin, D.; Melaimi, M.; Soleilhavoup, M.;
Bertrand, G. Organometallics 2011, 30, 5304−5313.
(4) Dyker, C. A.; Lavallo, V.; Donnadieu, B.; Bertrand, G. Angew.
Chem., Int. Ed. 2008, 47, 3206−3209.
(5) Viehe and Lach were the first to prepare allene B: (a) Furstner,
̈
A.; Alcarazo, M.; Goddard, R.; Lehmann, C. W. Angew. Chem., Int. Ed.
2008, 47, 3210−3214. (b) Viehe, H. G.; Janousek, Z.; Gompper, R.;
Lach, D. Angew. Chem., Int. Ed. 1973, 12, 566−567.
(6) A possible ambiguity may arise from the term “dicarbene”, which
has also been used to refer to five-membered heterocycles containing
two carbene centers. See the following: (a) Wang, Y.; Xie, Y.;
Abraham, M. Y.; Wei, P.; Schaefer, H. F., III; Schleyer, P. v. R.;
Robinson, G. H. J. Am. Chem. Soc. 2010, 132, 14370−14372.
(b) Wang, Y.; Abraham, M. Y.; Gilliard, R. J., Jr.; Wei, P.; Smith, J.
C.; Robinson, G. H. Organometallics 2012, 31, 791−793. (c) Wang, Y.;
Xie, Y.; Abraham, M. Y.; Gilliard, R. J., Jr.; Wei, P.; Campana, C. F.;
Schaefer, H. F., III; Schleyer, P. v. R.; Robinson, G. H. Angew. Chem.,
Int. Ed. 2012, 51, 10173−10176. (d) Yan, X.; Bouffard, J.; Guisado-
Barrios, G.; Donnadieu, B.; Bertrand, G. Chem. Eur. J. 2012, 18,
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dx.doi.org/10.1021/om400139s | Organometallics 2013, 32, 2435−2442