10.1002/anie.201808800
Angewandte Chemie International Edition
COMMUNICATION
[8]
For selected examples, see: a) L. Greb, S. Tamke, J. Paradies, Chem.
Commun. 2014, 50, 2318-2320; b) M. Pérez, C. B. Caputo, R.
Dobrovetsky, D. W. Stephan, Proc. Natl. Acad. Sci. USA 2014, 111,
10917-10921; c) R. Dobrovetsky, K. Takeuchi, D. W. Stephan, Chem.
Commun. 2015, 51, 2396-2398; d) Z-Y. Liu, Z-H. Wen, X-C. Wang,
Angew. Chem. Int. Ed. 2017, 56, 5817-5820; Angew. Chem. 2017, 129,
5911-5914.
Acknowledgements
We gratefully acknowledge the School of Chemistry, Cardiff
University for generous support, the Leverhulme Trust for a
Research Project Grant (IK, RPG-2015-361), the EPSRC
Doctoral Training Grant for a part-funded Ph.D. studentship
(B.G.R-B., EP/M507842/1), and the EPSRC UK National Mass
Spectrometry Facility at Swansea University.
[9]
a) H. Wang, R. Fröhlich, G. Kehr, G. Erker, Chem. Commun. 2008,
5966-5968; b) K. V. Axenov, G. Kehr, R. Fröhlich, G. Erker, J. Am.
Chem. Soc. 2009, 131, 3454-3455; c) L. Greb, P. Oña-Burgos, A.
Kubas, F. C. Falk, F. Breher, K. Fink, J. Paradies, Dalton Trans. 2012,
41, 9056-9060; d) S. Wei, H. Du, J. Am. Chem. Soc. 2014, 136, 12261-
12264; e) X. Ren, G. Li, S. Wei, H. Du, Org. Lett. 2015, 17, 990-993; f)
J. Yu, G. Kehr, C. G. Daniliuc, C. Bannwarth, S. Grimme, G. Erker, Org.
Biomol. Chem. 2015, 13, 5783-5782.
Conflict of interest
The authors declare no conflict of interest
[10] For transition metal catalyzed hydrogenation of silyl enol ethers, see: a)
S. Buksha, G. S. Coumbarides, M. Dingjan, J. Eames, M. J. Suggate, N.
Weerasooriya, J. Label. Compd. Radiopharm. 2006, 49, 757-771; b) T.
S. Carter, L. Guiet, D. J. Frank, J. West, S. P. Thomas, Adv. Synth.
Catal. 2013, 355, 880-884; c) K. Garcés, R. Lalrempuia, C. Polo, F. J.
Fernández-Alvarez, P. García-Orduña, F. J. Lahoz, J. J. Pérez-
Torrente, L. A. Oro, Chem. Eur. J. 2016, 22, 14717-14729; d) T. N.
Gieshoff, U. Chakraborty, M. Villa, A. Jacobi von Wangelin, Angew.
Chem. Int. Ed. 2017, 56, 3585-3589; Angew. Chem. 2017, 129, 3639-
3643.
Keywords: frustrated Lewis pairs • transfer hydrogenation •
metal free catalysis • silyl enol ethers • dihydrogen surrogates
[1]
For pioneering work, see: a) G. C. Welch, R. R. S. Juan, J. D. Masuda,
D. W. Stephan, Science 2006, 314, 1124-1126; b) G. C. Welch, D. W.
Stephan, J. Am. Chem. Soc. 2007, 129, 1880-1881. c) P. Spies, G.
Erker, G. Kehr, K. Bergander, R. Fröhlich, S. Grimme, D. W. Stephan,
Chem. Commun. 2007, 5072-5074. For selected reviews, see: d) D. W.
Stephan, G. Erker, Angew. Chem. Int. Ed. 2010, 49, 46-76; Angew.
Chem. 2010, 122, 50-81; e) T. Soós, Pure Appl. Chem. 2011, 83, 667-
675; f) J. Paradies, Angew. Chem. Int. Ed. 2014, 53, 3552-3557;
Angew. Chem. 2014, 126, 3642-3629; g) L. Shi, Y-G. Zhou,
ChemCatChem 2015, 7, 54-56; h) D. W. Stephan, G. Erker, Angew.
Chem. Int. Ed. 2015, 54, 6400-6441; Angew. Chem. 2015, 127, 6498-
6541; i) D. W. Stephan, J. Am. Chem. Soc. 2015, 137, 10018-10032; j)
D. W. Stephan, Acc. Chem. Res. 2015, 48, 306-316; k) D. W. Stephan,
Science 2016, 354, aaf7229; l) W. Meng, X. Feng, H. Du. Acc. Chem.
Res. 2018, 51, 191-201.
[11] I. Khan, M. Manzotti, G. J. Tizzard, S. J. Coles, R. L. Melen, L. C.
Morrill, ACS Catal. 2017, 7, 7748-7752.
[12] V. Sumerin, F. Shulz, M. Nieger, M. Leskelä, T. Repo, B. Rieger,
Angew. Chem. Int. Ed. 2008, 47, 6001-6003; Angew. Chem. 2008, 120,
6090-6092.
[13] See the Supporting Information for full experimental details.
[14] R. F. Childs, D. L. Mulholland, A. Nixon, Can. J. Chem. 1982, 60, 801-
808.
[15] J. A. Nicasio, S. Steinberg, B. Inés, M. Alcarazo, Chem. Eur. J. 2013,
19, 11016-11020.
[16] a) C. C. C. Johansson, Seechurn, M. O. Kitching, T. J. Colacot, V.
Snieckus, Angew. Chem. Int. Ed. 2012, 51, 5062-5085; Angew. Chem.
2012, 124, 5150-5174; b) P. Ruiz-Castillo, S. L. Buchwald, Chem. Rev.
2016, 116, 12564-12649; c) D. Haas, J. M. Hammann, R. Greiner, P.
Knochel, ACS Catal. 2016, 6, 1540-1552.
[2]
For selected reviews, see: a) D. W. Stephan, S. Greenberg, T. W.
Graham, P. Chase, J. J. Hastie, S. J. Geier, J. M. Farrell, C. C. Brown,
Z. M. Heiden, G. C. Welch, M. Ullrich, Inorg. Chem. 2011, 50, 12338-
12348; b) D. W. Stephan, Org. Biomol. Chem. 2012, 10, 5740-5746; c)
J. Paradies, Synlett, 2013, 24, 777-780; d) L. J. Hounjet, D. W. Stephan,
Org. Process Res. Dev. 2014, 18, 385-391; e) L. Shi, Y-G. Zhou,
ChemCatChem 2015, 7, 54-56; f) D. J. Scott, M. J. Fuchter, A. E.
Ashley, Chem. Soc. Rev. 2017, 46, 5689-5700.
[17] a) P. Spies, S. Schwendemann, S. Lange, G. Kehr, R. Frölich, G. Erker,
Angew. Chem. Int. Ed. 2008, 47, 7543-7546; Angew. Chem. 2008, 120,
7654-7657; b) V. Sumerin, F. Schulz, M. Atsumi, C. Wang, M. Nieger,
M. Leskelä, T. Repo, P. Pyykkö, B. Rieger, J. Am. Chem. Soc. 2008,
130, 14117-14119; c) K. Chernichenko, M. Nieger, M. Leskelä, T. Repo,
Dalton Trans. 2012, 41, 9029-9032; d) J. M. Farrell, J. A. Hatnean, D.
W. Stephan, J. Am. Chem. Soc. 2012, 134, 15728-15731; e) Ref 9f; f)
A. Klose, G. Kehr, C. G. Daniliuc, G. Erker, Dalton Trans. 2016, 45,
2023-2030; g) C. Rosorius, J. Möricke, B. Wibbeling, A. C. McQuilken,
T. H. Warren, C. G. Daniliuc, G. Kehr, G. Erker, Chem. Eur. J. 2016, 22,
1103-1113.
[3]
[4]
J. M. Farrell, Z. M. Heiden, D. W. Stephan, Organometallics 2011, 30,
4497-4500.
a) I. Chatterjee, M. Oestreich, Angew. Chem. Int. Ed. 2015, 54, 1965-
1968; Angew. Chem. 2015, 127, 1988-1991; b) I. Chatterjee, Z-W. Qu,
S. Grimme, M. Oestreich, Angew. Chem. Int. Ed. 2015, 54, 12158-
12162; Angew. Chem. 2015, 127, 12326-12330; c) W. Yuan, P.
Orecchia, M. Oestreich, Chem. Commun. 2017, 53, 10390-10393. For
a review, see d) S. Keess, M. Oestreich, Chem. Sci. 2017, 8, 4688-
4695.
[18] Although Scheme 3 depicts hydride abstraction at C(6), alternatively,
hydride abstraction could occur at C(3).
[5]
a) Q. Zhou, L. Zhang, W. Meng, X. Feng, J. Yang, H. Du, Org. Lett.
2016, 18, 5189-5191; b) F. Ding, Y. Zhang, R. Zhao, Y. Jiang, R. Li-
Yuan Bao, K. Lin, L. Shi, Chem. Commun. 2017, 53, 9262-9264.
Q. Wang, J. Chen, X. Feng, H. Du, Org. Biomol. Chem. 2018, 16, 1448-
1451.
[19] R. More O’Ferrall in Advances in Physical Organic Chemistry, Vol. 44
(Ed.: J. P. Richard), Academic Press, Oxford, 2010, pp. 12-122.
[20] For mechanistic discussions, see: a) J. Paradies, Angew. Chem. Int. Ed.
2014, 53, 3552-3557; Angew. Chem. 2014, 126, 3624-3629; b) Ref 2f.
[6]
[7]
a) S. Li, G. Li, W. Meng, H. Du, J. Am. Chem. Soc. 2016, 138, 12956-
12962; b) S. Li, W. Meng, H. Du, Org. Lett. 2017, 19, 2604-2606.
This article is protected by copyright. All rights reserved.