Journal of the American Chemical Society
Communication
+
−
entry 5, mixing Cp*Ru(CH CN) PF and the requisite
AUTHOR INFORMATION
Notes
3
3
6
phosphine (1 mol % each) to afford 3 + CH CN (nitrile/Ru
3
ratio 3:1) was just as effective, offering a convenient alternative.
In summary, the precise ratio of 1 to 3 in the catalyst does not
seem to affect rate or selectivity of isomerization, and 3 +
The authors declare no competing financial interest.
CH CN formed in situ gives the same selectivity, with slightly
3
reduced rate (∼1/2) that seen using 1 + 3 mixtures.
ACKNOWLEDGMENTS
■
Table 2 shows that compounds that are functionalized and
protic can also be converted to (E)-2-alkenes with high selectivity
using 1 mol % 1 + 3. Pent-4-en-1-ol is easily transformed into
NSF supported this work (CHE-1059107) and upgrade of the
departmental NMR facility. We thank Erik Paulson for carrying
out the control experiment for entry 2d in Table 1.
>
94% 3-penten-1-ol within 24 h (entry 1). The monoisomeriza-
tion of 4-penten-1-ol with cis-Pt(DMSO) Cl in water only gave
2
2
REFERENCES
(1) Plotkin, J. S. Catal. Today 2005, 106, 10.
2) Otsuka, S.; Tani, K. In Transition Metals for Organic Synthesis, 2nd
ed.; Beller, M., Bolm, C., Eds.; Wiley-VCH: Weinheim, Germany, 2004;
■
5
0% conversion to 3-penten-1-ol, after one day, with no mention
12a
of geometric selectivity. The corresponding silyl ether (entry
) can be smoothly converted to the trans-monoisomerized
product, without overisomerization at 40 °C and not until 23 h at
0 °C (2.5%). Lim et al. reported the promising monoisomeriza-
(
2
Vol. 1, pp 199−209.
7
(
́ ́
3) Examples of reviews: (a) Uma, R.; Crevisy, C.; Gree, R. Chem. Rev.
tion of the hexenyl homologue of entry 2 with two multi-
component catalysts ((allyl)Pd or Ni halide dimer, phosphine,
2003, 103, 27. (b) Kuznik, N.; Krompiec, S. Coord. Chem. Rev. 2007,
251, 222. (c) Krompiec, S.; Krompiec, M.; Penczek, R.; Ignasiak, H.
Coord. Chem. Rev. 2008, 252, 1819.
1
2b
and AgOTf) in 80−95% yield but with E/Z ratios near 3.7:1,
13
(
4) Walsh, P. J., Kozlowski, M. C. Fundamentals of Asymmetric
probably close to the thermodynamic values. Here, entries 4
Catalysis; University Science Books: Mill Valley, CA, 2009. Jacobsen, E.
N.; Pfaltz, A.; Yamamoto, H. Comprehensive Asymmetric Catalysis;
Springer: Berlin, 1999.
5) Best literature results for selective formation of linear 2-alkenes:
a) McGowan, K. P.; Abboud, K. A.; Veige, A. S. Organometallics 2011,
0, 4949. (b) Krompeic, S.; Suwinski, J.; Grobelny, J. Pol. J. Chem. 1996,
70, 813. (c) Sivaramakrishna, A.; Mushonga, P.; Rogers, I. L.; Zheng, F.;
Haines, R. J.; Nordlander, E.; Moss, J. R. Polyhedron 2008, 27, 1911.
(d) Chianese, A. R.; Shaner, S. E.; Tendler, J. A.; Pudalov, D. M.;
Shopov, D. Y.; Kim, D.; Rogers, S. L.; Mo, A. Organometallics 2012, 31,
7359. (e) Jennerjahn, R.; Jackstell, R.; Piras, I.; Franke, R.; Jaio, H.;
Bauer, M.; Beller, M. ChemSusChem 2012, 5, 734. (f) Mayer, M.;
Welther, A.; von Wangelin, A. J. ChemCatChem 2011, 3, 1567.
and 5 show that longer chains bearing an alcohol at the remote
end work equally well, neither being slowed nor suffering from
reduced positional or geometric selectivity.
(
(
3
Initial experiments with aromatic reactants suggested that they
were not well-tolerated by 1 + 3, whereas they are by CpRu
6
‑
analog 2a. The tert-butyldiphenylsilyl ether of pent-4-en-1-ol
was transformed to the product of interest (29%) but catalyst
deactivation occurred by liberation of the phosphine ligand and
what appeared to be irreversible arene complex formation (as
3
1
evidenced by loss of P NMR peaks for 1 and 3, appearance of a
1
peak for free phosphine, and appearance of H resonances
between 5.9 and 6.2 ppm tentatively assigned to metalated
arene). Perhaps because of release of steric strain, dissociative
phosphine loss from 1 and 3 is more pronounced than from 2a.
(
1
g) Kobayashi, T.; Yorimitsu, H.; Oshima, K. Chem. Asian J. 2009, 4,
078. (h) Chen, C.; Dugan, T. R.; Brennessel, W. W.; Weix, D. J.;
Holland, P. L. J. Am. Chem. Soc. 2014, Published Online: Jan 3, 2014.
(6) (a) Grotjahn, D. B.; Larsen, C. R.; Gustafson, J. L.; Nair, R.;
Sharma, A. J. Am. Chem. Soc. 2007, 129, 9592. (b) Larsen, C. R.;
Grotjahn, D. B. J. Am. Chem. Soc. 2012, 134, 10357. (c) Larsen, C. R.;
Grotjahn, D. B. J. Am. Chem. Soc. 2012, 134, 15604. (d) Erdogan, G.;
Grotjahn, D. B. J. Am. Chem. Soc. 2009, 131, 10354. (e) Erdogan, G.,
Ph.D. Thesis, University of California at San Diego and San Diego State
University, 2012.
7) Morrill, T. C.; D’Souza, C. A. Organometallics 2003, 22, 1626.
8) Bouziane, A.; Carboni, B.; Bruneau, C.; Carreaux, F.; Renaud, J.-L.
Tetrahedron 2008, 64, 11745.
9) (a) We thank two reviewers for suggesting these control
+
3
−
We note that phosphine-free species Cp*Ru(CH CN) PF is
3
6
a poor catalyst (Table 1, entry 2d), so the activity and high
selectivity exhibited by 1 + 3 requires the phosphine.
Importantly, solving the arene binding problem is possible.
The successful result of Table 2, entry 3, was achieved with 2 mol
%
1 + 3 and added bifunctional imidazolylphosphine ligand (6
mol %), which suppressed Cp*Ru-arene complex formation
enough to allow for >90% yield of monoisomerized product to
form.
(
(
+
In summary, we show that a new Cp*Ru catalyst comprising
+ 3 offers unparalleled catalyst control of both position and
(
1
experiments; full analysis in SI. (b) A separate control experiment on
(E)-3-heptene after 22 h at 40 °C led to 0.9% (E)-2-heptene, but no
detectable 1-heptene. (c) Grotjahn, D. B.; Erdogan, G.; Larsen, C. L.,
unpublished results.
geometry in the isomerization of 1-alkenes to (E)-2-alkenes, with
product yields typically about 95% even when polar substituents
are present. Protic and carbonyl (acetone solvent) functional
groups are tolerated; neither strong base, nucleophile, nor acid is
present. The preformed catalyst and 3 formed conveniently in
situ show the same high catalyst control. Both the Cp* and
bifunctional ligands are absolutely essential for activity and
selectivity. The results here are part of an ongoing program to
build a toolbox of catalysts and chemistry for selective alkene
transformation, and further reports will appear in due course.
(
10) (a) Grotjahn, D. B.; Gong, Y.; DiPasquale, A. G.; Zakharov, L. N.;
Rheingold, A. L. Organometallics 2006, 25, 5693. (b) Grotjahn, D. B.;
Gong, Y.; Zakharov, L. N.; Golen, J. A.; Rheingold, A. L. J. Am. Chem.
Soc. 2006, 128, 438.
(
11) Luginbu
B.; Merbach, A. E.; Ludi, A. Inorg. Chem. 1991, 30, 2350.
(12) (a) Aleman, J.; del Solar, V.; Cubo, L.; Quiroga, A. G.; Navarro
̈ ̈
hl, W.; Zbinden, P.; Pittet, P. A.; Armbruster, T.; Burgi, H.
́
Ranninger, C. Dalton Trans. 2010, 39, 10601. (b) Lim, H. J.; Smith, C.
R.; RajanBabu, T. V. J. Org. Chem. 2009, 74, 4565.
(
13) Dec-9-en-1-ol isomerizes in the presence of a Ru−H complex at
ASSOCIATED CONTENT
1
■
70 °C to an internal isomer, likely dec-8-en-1-ol on the basis of H NMR
spectroscopy Lee, J. P.; Ke, Z.; Ramirez, M. A.; Gunnoe, T. B.; Cundari,
T. R.; Boyle, P. D.; Petersen, J. L. Organometallics 2009, 28, 1758.
*
S
Supporting Information
Details of catalyst preparation, spectra, characterization and
D
dx.doi.org/10.1021/ja411438d | J. Am. Chem. Soc. XXXX, XXX, XXX−XXX