Organic Letters
Letter
Applications of Olefin Metathesis Polymerizations. In Olefin Metathesis
Theory and Practice; Grela, K., Ed.; John Wiley & Sons: Hoboken, NJ,
United States, 2014.
Table 4. CM of 1-Hexene (20) in the Presence of Complex 9g
(4) (a) Kong, J.; Chen, C.-y.; Balsells-Padros, J.; Cao, Y.; Dunn, R. F.;
Dolman, S. J.; Janey, J.; Li, H.; Zacuto, M. J. J. Org. Chem. 2012, 77, 3820.
(b) Shu, C.; Zeng, X.; Hao, M.-H.; Wei, X.; Yee, N. H.; Busacca, C. A.;
Han, Z.; Farina, V.; Senanayake, C. H. Org. Lett. 2008, 10, 1303.
a
b
entry
temp (°C)
conversion (%)
1
2
3
4
23
50
75
95
<5
8
(
5) For representative reviews on ligand classes, see corresponding
chapters in ref 2a.
6) See: Kuethe, J.; Zhong, Y.-L.; Yasuda, N.; Beutner, G.; Linn, K.;
27
90
(
Kim, M.; Marcune, B.; Dreher, S. D.; Humphrey, G.; Pei, T. Org. Lett.
2013, 15, 4174 and references therein.
a
Conditions: The concentration of 1-hexene (20) in toluene-d was
8
0
.5 M, and the reactions were carried out in a sealed tube under a
(
7) The manuscript related to this subject matter is currently in
preparation and will be reported in due time.
8) The reaction proceeded to 100% conversion over 1 h with 5 equiv
of 1,4-diacetoxy-cis-2-butene at 80 °C.
9) The serendipitous discovery of novel OM complexes has occurred
nitrogen atmosphere. Conversion was determined via 1H NMR
spectroscopy where product was cleanly observed.
b
(
(
experiment highlights one of the unique properties of this
catalyst in its ability to modulate reactivity based on reaction
temperature.
previously. See: (a) Kingsbury, J. S.; Harrity, J. P. A.; Bonitatebus, P. J.,
Jr.; Hoveyda, A. H. J. Am. Chem. Soc. 1999, 121, 791. (b) Tallarico, J. A.;
Bonitatebus, P. J., Jr.; Snapper, M. L. J. Am. Chem. Soc. 1997, 119, 7157.
(10) A variety of commercial N-heterocyclic carbene (NHC)-
containing OM catalysts were utilized as the starting material.
In summary, we have transformed a serendipitous discovery of
an intermediate Ru-complex derived from our work on the
synthesis of grazoprevir (MK-5172) into a highly tunable
metathesis catalyst class. The ruthenium complexes are isolated
in good to excellent yields, are shelf- and solution-stable for
extended periods, and exhibit wide-ranging metathesis activities
including active to latent catalysis. Furthermore, we have
successfully designed and explored a strategy for modulating
metathesis reactivity using acids as competent co-catalysts or by
modulating the reaction temperature.
(11) Complex 9a demonstrated solution stability up to 30 days in
CD Cl at room temperature under nitrongen, and the solid material
2
2
showed shelf stability up to 6 months.
12) (a) Szadkowska, A.; Gstrein, X.; Burtscher, D.; Jarzembska, K.;
Wozniak, K.; Slugovc, C.; Grela, K. Organometallics 2010, 29, 117.
b) Barbasiewicz, M.; Szadkowska, A.; Bujok, R.; Grela, K. Organo-
(
(
metallics 2006, 25, 3599. (c) Ung, T.; Hejl, A.; Grubbs, R. H.; Schrodi, Y.
Organometallics 2004, 23, 5399. (d) Puentener, K.; Scalone, M. New
ruthenium complexes as catalysts for metathesis reactions. Eur. Pat.
Appl. EP2008154367A, 2008. (e) Diesendruck, C. E.; Tzur, E.; Ben-
Asuly, A.; Goldberg, I.; Straub, B. F.; Lemcoff, N. G. Inorg. Chem. 2009,
ASSOCIATED CONTENT
Supporting Information
■
4
8, 10819.
*
S
(13) Alternative reaction kinetics can be obtained by modulating the
electronics and sterics of the alkoxybenzylidene ligand. For
representative examples, see: (a) Engle, K. M.; Lu, G.; Luo, S.-X.;
Henling, L. M.; Takase, M. K.; Liu, P.; Houk, K. N.; Grubbs, R. H. J. Am.
Chem. Soc. 2015, 137, 5782. (b) Michrowska, A.; Grela, K. Pure Appl.
Chem. 2008, 80, 31.
Crystallographic data (CIF)
(14) For promotion of metathesis with acid, see: (a) Keitz, B. K.;
Bouffard, J.; Bertrand, G.; Grubbs, R. H. J. Am. Chem. Soc. 2011, 133,
8498 and references therein. For references regarding the effect of
Brønsted acids on polytopal rearrangements of Ru complexes, see:
AUTHOR INFORMATION
■
*
*
(
b) Gulajski, L.; Michrowska, A.; Bujok, R.; Grela, K. J. Mol. Catal. A:
Chem. 2006, 254, 118.
15) The AlCl ·THF complex was chosen because of the potential
(
3
Notes
application toward Brønsted acid sensitive functionality.
16) For reviews on latent OM catalysis, see: (a) Reference 2a.
b) Monsaert, S.; Vila, A. L.; Drozdzak, R.; Van Der Voort, P.; Verpoort,
(
The authors declare no competing financial interest.
(
F. Chem. Soc. Rev. 2009, 38, 3360. For select examples, see: (c) Rouen,
M.; Queval, P.; Falivene, L.; Allard, J.; Toupet, L.; Crevisy, C.; Caijo, F.;
Basle, O.; Cavallo, L.; Mauduit, M. Chem. - Eur. J. 2014, 20, 13716.
(d) Thomas, R. M.; Fedorov, A.; Keitz, B. K.; Grubbs, R. H.
Organometallics 2011, 30, 6713. (e) Hejl, A.; Day, M. W.; Grubbs, R.
H. Organometallics 2006, 25, 6149.
ACKNOWLEDGMENTS
■
We thank Becky Ruck (Merck) for helpful discussions,
suggestions, and editing. We thank Erin Guidry (Merck) for
helpful discussions. Finally we thank Renee K. Dermenjian
(
Merck) and Claudia Monteiro (Merck) for help obtaining
characterization data.
REFERENCES
■
(
2
1) (a) Werrel, S.; Walker, J. C. L.; Donohoe, T. J. Tetrahedron Lett.
015, 56, 5261. (b) Olszewski, T. K.; Bieniek, M.; Skowerski, K.; Grela,
K. Synlett 2013, 24, 903. (c) Nicolaou, K. C.; Bulger, P. G.; Sarlah, D.
Angew. Chem., Int. Ed. 2005, 44, 4490.
(
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(
Olefin Metathesis Theory and Practice; Grela, K., Ed.; John Wiley & Sons:
Hoboken, NJ, United States, 2014. (b) Slugovc, C. Industrial
D
Org. Lett. XXXX, XXX, XXX−XXX