10.1002/anie.201812984
Angewandte Chemie International Edition
COMMUNICATION
[8]
[9]
a) K. P. J. Gustafson, A. Guðmundsson, K. Lewis, J.-E. Bäckvall,
Chem. Eur. J. 2017, 23, 1048–1051; b) O. Pàmies, J.-E. Bäckvall,
Chem. Rev. 2003, 103, 3247–3262; c) O. Verho, J. E. Bäckvall, J. Am.
Chem. Soc. 2015, 137.
pinacolboranes and free alcohols. The obtained products could
find use as important building blocks for the synthesis of small-
molecule pharmaceuticals containing pyrazoles.
For reviews and definitions see: a) F. F. Huerta, A. B. E. Minidis, J.-E.
Bäckvall, Chem Soc Rev 2001, 30, 321–331; b) R. S. Ward,
Tetrahedron Asymmetry 1995, 6, 1475–1490; c) R. Noyori, M.
Tokunaga, M. Kitamura, Bull. Chem. Soc. Jpn. 1995, 68, 36–55.
Acknowledgements
[10] J. Lloyd, H. J. Finlay, W. Vacarro, T. Hyunh, A. Kover, R. Bhandaru, L.
Yan, K. Atwal, M. L. Conder, T. Jenkins-West, et al., Bioorg. Med.
Chem. Lett. 2010, 20, 1436–1439.
This work supported by the Deutsche Forschungsgemeinschaft
(DFG) and the Fonds der Chemischen Industrie. Jan Klauser
(University of Freiburg) is acknowledged for his motivated
technical assistance. Sincere thanks are given to Dr. Manfred
Keller for NMR experiments, analysis of isomers and Joshua
Emmerich for HPLC separations.
[11] a) J. C. Byrd, et al., N. Engl. J. Med. 2013, 369, 32–42; b) A. Turetsky,
E. Kim, R. H. Kohler, M. A. Miller, R. Weissleder, Sci. Rep. 2014, 4, 1–7.
[12] a) S. Verstovsek, et al., N. Engl. J. Med. 2012, 366, 799–807; b) R. A.
Mesa, U. Yasothan, P. Kirkpatrick, Nat. Rev. Drug Discovery 2012, 11,
103–104; c) P. Koppikar, et al., Nature 2012, 489, 155–159.
[13] For N-containing heterocycles see: a) E. Vitaku, D. T. Smith, J. T.
Njardson, J. Med. Chem. 2014, 57,10257-10274; b) C. Lamberth, J.
Dinges, Bioactive Heterocyclic Compound Classes: Pharmaceuticals
and Agrochemicals, Wiley-VCH, Weinheim, 2012; c) W. Kramer, U.
Schirmer, P. Jeschke, M. Witschel, Modern Crop Protection
Compounds, Wiley-VCH, Weinheim, 2011.
Conflict of interest
[14] For biological activities see: a) J. Alvarez-Builla, J. J. Vaquero, J.
Barluenga, Modern Hetercyclic Chemistry Vol. 2, Wiley-VCH, Weinheim,
2011; b) A. Schmidt, A. Dreger, Curr. Org. Chem. 2011, 15, 1423-1463.
[15] For determination of absolute configuration, see supporting information.
[16] a) G. Xu, S. R. Gilbertson, Org. Lett. 2005, 7, 4605–4608; b) B.
Bhayana, B. P. Fors, S. L. Buchwald, Org. Lett. 2009, 11, 3954–3957;
c) R. S. Foster, H. Adams, H. Jakobi, J. P. A. Harrity, J. Org. Chem.
2013, 78, 4049–4064.
The authors declare no conflict of interest.
Keywords: Dynamic Kinetic Resolution • Palladium • Rhodium •
Pyrazole • Internal Allene • Asymmetric Catalysis
[1]
[2]
For recent reviews, see: a) P. Koschker, B. Breit, Acc. Chem. Res.
2016, 49, 1524-1536; b) A. M. Haydl, B. Breit, T. Liang, M. J. Krische,
Angew. Chem. Int. Ed. 2017, 56, 11312–11325; Angew. Chem. 2017,
129, 11466–11480.
[17] J. Catalán, J. L. G. de Paz, J. Elguero, J Chem Soc Perkin Trans 2
1996, 57–60.
[18] For conditions, see supporting information.
For recent publications of our group, see: a) Y. Zhou, B. Breit, Chem.
Eur. J. 2017, 23, 18156–18160; b) Z. Liu, B. Breit, Org. Lett. 2018, 22,
300-303; c) C. Grugel, B. Breit, Org. Lett. 2018, 20, 1066–1069; d) D.
Berthold, B. Breit, Org. Lett. 2018, 20, 598–601; e) P. Steib, B. Breit,
Angew. Chem. Int. Ed. 2018, 57, 6572–6576; P. Steib, B. Breit, Angew.
Chem. 2018, 130, 6682–6686; f) J. Zheng, B. Breit, Org. Lett. 2018, 20,
1866–1870; g) P. Spreider, B. Breit, Org. Lett. 2018, 20 (4), 3286–3290.
B. Trost, Science 1991, 254, 1471–1477.
[19] No racemization occurred in absence of [Pd] or [Rh].
[20] For a publication of rhodium-catalyzed racemization of internal allenes
of our group, see: A. B. Pritzius, B. Breit, Angew. Chem. Int. Ed. 2015,
54, 15818–15822; Angew. Chem. 2015, 127, 16044–16048.
[21] For recent publication of similar mechanism, see: D. N. Tran, N.
Cramer, Angew. Chem. Int. Ed. 2013, 52, 10630–10634; Angew. Chem.
2013, 125, 10824–10828.
[3]
[4]
[22] For first dynamic kinetic resolution of internal allenes, see: J. Deska, C.
del Pozo Ochoa, J.-E. Bäckvall, Chem. Eur. J. 2010, 16, 4447–4451.
[23] For rhodium-catalyzed racemization of allenes, see: J. D. Osborne, H.
E. Randell-Sly, G. S. Currie, A. R. Cowley, M. C. Willis, J. Am. Chem.
Soc. 2008, 130, 17232-17233.
a) B. M. Trost, Chem. Rev. 1996, 96, 395–422; b) B. M. Trost, M. L.
Crawley, Chem. Rev. 2003, 103, 2921–2943; c) Z. Lu, S. Ma, Angew.
Chem. Int. Ed. 2008, 47, 258–297; d) T. Hayashi, A. Okada, T. Suzuka,
M. Kawatsura, Org. Lett. 2003, 5, 1713–1715; e) P. A. Evans, D. K.
Leahy, J. Am. Chem. Soc. 2002, 124, 7882–7883; f) J. Qu, G.
Helmchen, Acc. Chem. Res. 2017, 50, 2539–2555; g) S. T.
Madrahimov, Q. Li, A. Sharma, J. F. Hartwig, J. Am. Chem. Soc. 2015,
137, 14968-14981; h) D. A. Petrone, M. Isomura, I. Franzoni, S. L.
Rössler, E. M. Carreira, J. Am. Chem. Soc. 2018, 140, 4697-4704.
a) G. Liu, Y. Wu, Top. Curr. Chem. 2010, 292, 195–209; b) M. S. Chen,
M. C. White, J. Am. Chem. Soc. 2004, 126, 1346–1347; c) G. Liu, S. S.
Stahl, J. Am. Chem. Soc. 2007, 129, 6328–6335.
[24] For palladium-catalyzed racemization of allenes, see: A. Horváth, J.-E.
Bäckvall, Chem. Commun. 2004, 964-965.
[25] For copper-catalyzed racemization of allenes, see: A. Claesson, L. I.
Olsson, J. Chem. Soc. Chem. Commun. 1979, 12, 524-525.
[26] For
a
mechanistic proposal of the Pd- and Rh-catalyzed
[5]
[6]
[7]
hydroamination of internal allenes, see supporting information.
[27] For Rh-catalyzed isomerizations in absence of acid, see: J. C.
Trebellas, J. R. Olechowski, H. B. Jonassen, D. W. Moore, J.
Organomet. Chem. 1967, 9, 153–158.
a) A. M. Haydl, L. J. Hilpert, B. Breit, Chem. Eur. J. 2016, 22, 6547-
6551; b) A. M. Haydl, K. Xu, B. Breit, Angew. Chem. Int. Ed. 2015, 54,
7149-7153; Angew. Chem. 2015, 127, 7255-7259.
For recent reviews on internal allenes, see: a) J. Ye, S. Ma, Org Chem
Front 2014, 1, 1210–1224; b) S. Ma, Chem. Rev. 2005, 105, 2829–
2872.
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