10.1002/chem.201804308
Chemistry - A European Journal
COMMUNICATION
Catal. 2016, 6, 4184; g) N. Deibl, R. Kempe, J. Am. Chem. Soc. 2016,
138, 10786; h) F. Freitag, T. Irrgang, R. Kempe, Chem. Eur. J. 2017, 23,
12110; i) G. Zhang, J. Wu, H. Zeng, S. Zhang, Z. Yin, S. Zheng, Org. Lett.
2017, 19, 1080; j) W. M. Akhtar, C. B. Cheong, J. R. Frost, K. E.
Christensen, N. G. Stevenson, T. J. Donohoe, J. Am. Chem. Soc. 2017,
139, 2577.
[3]
[4]
[5]
P. T. Anastas, J. C. Warner, Green Chemistry: Theory and Practice,
Oxford University Press: New York, 1998, p. 30.
D. Prat, A. Wells, J. Hayler, H. Sneddon, C. R. McElroy, S. Abou-
Shehada, P. Dunn, Green Chem. 2016, 18, 288.
For selected reviews see: a) R. Breslow, J. Phys. Org. Chem. 2006, 19,
813; b) ) R. N. Butler, A. G. Coyne, Org. Biomol. Chem. 2016, 14, 9945;
c) B. H. Lipshutz, S. Ghorai, M. Cortes-Clerget, Chem. Eur. J. 2018, 24,
6672; d) T. Kitanosono, K. Masuda, P. Xu, S. Kobayashi, Chem. Rev.
2018, 118, 679;
Scheme 2. Scale-up (A) and room temperature (B) experiment for the model
reaction; the temperature of reaction B was recorded and determined to be
27 °C; isolated yields are given.
[6]
[7]
a) O. Saidi, A. J. Blacker, G. W. Lamb, S. P. Marsden, J. E. Taylor, J. M.
J. Williams, Org. Process Res. Dev. 2010, 14, 1046; b) O. Saidi, A. J.
Blacker, M. M. Farah, S. P. Marsden, J. M. J. Williams, Chem. Commun.
2010, 46, 1541; c) R. Kawahara, K. Fujita, R. Yamaguchi, J. Am. Chem.
Soc. 2010, 132, 15108.
In conclusion, a protocol for the catalytic α-alkylation of
various methyl ketones with benzyl and alkyl alcohols in water
was developed yielding the products in moderate to good yields.
Crucially, the efficiency of this reaction was significantly assisted
by the addition of CTAB, which is believed to function as a phase-
transfer catalyst and a surfactant. Overall, this protocol proceeds
under mild conditions, tolerates a broad variety of functional
groups and proceeds well even at room temperature. Unlike
traditional borrowing hydrogen reactions refluxing temperatures
were not required. Since all substrates, the additive and catalyst
are commercially available, we hope this mild and user-friendly
protocol will see immediate use in a variety of applications.
a) R. Kawahara, K.-I. Fujita, R. Yamaguchi, Adv. Synth. Catal. 2011, 353,
1161; b) H. Ohta, Y. Yuyama, Y. Uozumin, Y. M. A. Yamada, Org. Lett.
2011, 13, 3892; c) A. Wetzel, S. Wöckel, M. Schelwies, M. K. Brinks, F.
Rominger, P. Hofmann, M. Limbach, Org. Lett. 2013, 15, 266; d) Y. M. A.
Yamada, H. Ohta, Y. Yuyama, Y. Uozumi, Synthesis 2013, 2093; e) A.
Fernandes, B. Royo, ChemCatChem 2017, 23, 3912; f) C. Ge, X. Sang,
W, Yao, L. Zhang, D. Wang, Green Chem. 2018, 20, 1805.
C. Gunanathan, D. Milstein, Angew. Chem. Int. Ed. 2008, 47, 8661.
Z. Xu, X. Yu, X. Sang, D. Wang, Green Chem. 2018, 20, 2571.
[8]
[9]
[10] a) G. Xu, Q. Li, J. Feng, Q. Liu, Z. Zhang, X. Wang, X. Zhang, X. Mu,
ChemSusChem 2014, 7, 105; b) H. Hikawa, K. Izumi, Y. Ino, S. Kikkawa,
Y. Yokoyama, I. Azumaya, Adv. Synth. Catal. 2015, 357, 1037; c) H.
Hikawa, T. Koike, K. Izumi, S. Kikkawa, I. Azumaya, Adv. Synth. Catal.
2016, 358, 784; d) H. Hikawa, R. Ichinose, S. Kikkawa, I. Azumaya,
Green Chem. 2018, 20, 1297; e) H. Hikawa, H. Imamura, S. Kikkawa, I.
Azumaya, Green Chem. 2018, 20, 3044.
Acknowledgements
[11] For selected examples, that benefit from surfactant addition, see: a) S.
R. K. Minkler, B. H. Lipshutz, N. Krause, Angew. Chem. Int. Ed. 2011,
50, 7820; b) D. Kumar, K. Seth, D. N. Kommi, S. Bhagat, A. K.
Chakraborti, RSC Advances, 2013, 3, 15157; c) P. Wagner, M.
Bollenbach, C. Doebelin, F. Bihel, J.-J. Bourguignon, C. Salomé, M.
Schmitt, Green Chem. 2014, 16, 4170; d) P. Klumphu, B. H. Lipshutz, J.
Org. Chem. 2014, 79, 888; e) A. Rühling, H.-J. Galla, F. Glorius, Chem.
Eur. J. 2015, 21, 12291; f) S. Wallace, E. P. Balskus, Angew. Chem. Int.
Ed. 2016, 55, 6023; g) V. R. Bhonde, B. T. O’Neill, S. L. Buchwald,
Angew. Chem. Int. Ed. 2016, 55, 1849.
The Deutsche Forschungs Gemeinschaft (SFB 858) is gratefully
acknowledged for generous financial support. The authors thank
Cornelia Weitkamp for great experimental support, Sven Sagebiel
for microscopy measurements and Dr. Christoph Schlepphorst,
Mario P. Wiesenfeldt, Dr. Michael J. James, Lena Pitzer and Prof.
Bart Jan Ravoo (all WWU) for helpful discussions.
[12] T. F. Tadros in Emulsion Formation and Stability (Ed.: T. F. Tadros),
Weinheim, VCH, 2013, pp. 1 – 75.
Keywords: borrowing hydrogen catalysis • phase-transfer
catalysis • ketone alkylation • reactions in water
[13] Breslow
observed
a
pseudo-detergent-like
character
of
tetrabutylammonium bromide, which resulted in the enhanced solubility
of benzene in polar solvents: R. Breslow, T. Guo, J. Am. Chem. Soc.
1988, 110, 5613.
[1]
For selected reviews see: a) M. H. S. A. Hamid, P. A. Slatford, J. M. J.
Williams, Adv. Synth. Catal. 2007, 349, 1555; b) G. Guillena, D. J.
Ramón, M. Yus, Angew. Chem. Int. Ed. 2007, 46, 2358; c) G. E.
Dobereiner, R. H. Crabtree, Chem. Rev. 2010, 110, 681; d) Y. Obora,
ACS Catal. 2014, 4, 3972; e) Y. Obora, Top Curr. Chem. 2016, 374, 11;
f) F. Huang, Z. Liu, Z. Yu, Angew, Chem. Int. Ed. 2016, 55, 862; g) A.
Corma, J. Navas, M. J. Sabater, Chem. Rev. 2018, 118, 1410.
[14] a) K. D. Collins, F. Glorius, Nat. Chem. 2013, 5, 597; b) K. D. Collins, A.
Rühling, F. Glorius, Nat. Protoc. 2014, 9, 1348; c) T. Gensch, M. Teders,
F. Glorius, J. Org. Chem. 2017, 82, 9154. d) For a review on the
evaluation of reactions by screening, see: K. D. Collins, F. Glorius, Acc.
Chem. Res. 2015, 48, 619.
[2]
For selected, recent literature on the alkylation of ketones with alcohols
see: a) S. Liao, K. Yu, Q. Li, H. Tian, Z. Zhang, X. Yu, Q. Xu, Org. Biomol.
Chem. 2012, 10, 2973; b) S. Srimani, E. Balaraman, B. Gnanaprakasam,
Y. Ben-David, D. Milstein, Adv. Synth. Catal. 2012, 354, 2403; c)
S.Elangovan, J.-B. Sortais, M. Beller, C. Darcel, Angew. Chem. Int. Ed.
2015, 54, 14483; d) S. Chakraborty, P. E. Piszel, C. E. Hayes, R. T.
Baker, W. D. Jones, J. Am. Chem. Soc. 2015, 137, 14264; e) M. Pería-
López, P. Piehl, S. Elangovan, H. Neumann, M. Beller, Angew. Chem.
Int. Ed. 2016, 55, 14967; f) C. Schlepphorst, B. Maji, F. Glorius, ACS
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