10.1002/chem.201804455
Chemistry - A European Journal
FULL PAPER
[6]
[7]
J. L. G. Ruano, E. Torrente, A. M. Martín-Castro, J. Org. Chem. 2011,
76, 3597.
are formed stereospecifically by the hydroboration of α,β-
unsaturated ketones
1
with (–)-Ipc2BH. Furthermore,
(a) R. Chowdhury, J. Schörgenhumer, J. Novacek, M. Waser,
Tetrahedron Lett. 2015, 56, 1911; b) M. Chen, Z.-T. Huang, Q.-Y.
Zheng, Org. Biomol. Chem. 2015, 13, 8812; c) J.-S. Qiu, Y.-F. Wang,
G.-R. Qi, P. G. Karmaker, H.-Q. Yin, F.-X. Chen, Chem. Eur. J. 2017,
23, 1775; d) B. Ma, X. Lin, L. Lin, X. Feng, X. Liu, J. Org. Chem. 2017,
82, 701; e) P. G. Karmaker, J. Qiu, D. Wu, M. Reng, Z. Yang, H. Yin,
F.-X. Chen, Org. Biomol. Chem. 2017, 15, 7753; f) P. G. Karmaker, J.
Qiu, D. Wu, S. Zhang, H. Yin, F.-X. Chen, Tetrahedron Lett. 2018, 59,
2034.
computational studies on the transition states indicates that an
unprecedented six-membered ring transition state is formed in
the cyanation step and this provides a reasonable explanation
for the high enantioselectivity observed for these reactions.
Finally, the present study provides a new type of reaction that
allows the construction of a chiral quaternary carbon center at
the α-position of a ketone.[19]
[8]
[9]
K. Buttk, H.-J. Niclas, J. Prakt. Chem. 1998, 340, 669.
K. Kiyokawa, T. Nagata, S. Minakata, Angew. Chem. Int. Ed. 2016, 55,
10458; Angew. Chem. 2016, 128, 10614.
Acknowledgements ((optional))
[10] Selected examples for reactions via activation of a cyano group by a
boron Lewis acid, see: a) H. Hamana, T. Sugasawa, Chem. Lett. 1985,
14, 571; b) C. A. Tolman, W. C. Seidel, J. D. Druliner, P. J. Domaille,
Organometallics 1984, 3, 33; c) N. M. Brunkan, D. M. Brestensky, W. D.
Jones, J. Am. Chem. Soc. 2004, 126, 3627; d) Y. Nakao, A. Yada, S.
Ebata, T. Hiyama, J. Am. Chem. Soc. 2007, 129, 2428; e) Y. Nakao,
Bull. Chem. Soc. Jpn. 2012, 85, 731; f) T. Nagata, H. Matsubara, K.
Kiyokawa, S. Minakata, Org. Lett. 2017, 19, 4672.
This work was supported by JSPS KAKENHI Grant Numbers
JP18J10497 (T.N.), JP18K14217 (K.K.), and JP17KT0011
(M.Y.). We thank Dr. Norimitsu Tohnai (Osaka University) for
assistance with X-ray crystallographic analysis.
[11] For reviews on asymmetric aldol reactions using boron enolates, see:
a) C. J. Cowden, I. Paterson, In Organic Reactions; Denmark, S., Ed.;
John Wiley & Sons, Inc.: New York, 1997; Vol. 51, p 1; b) A. Abiko, In
Boron Enolate Chemistry; Coca, A., Ed.; Boron Reagents in Synthesis;
American Chemical Society: Washington, DC, 2016; Vol. 1236, p 123.
[12] a) H. C. Brown, B. Singaram, J. Org. Chem. 1984, 49, 945; b) H. C.
Brown, J. V. N. V. Prasad, M. Zaidlewicz, J. Org. Chem. 1988, 53, 2911.
[13] CCDC 1856484 contains the supplementary crystallographic data for
this paper.
Conflicts of interest
The authors declare no conflict of interest.
Keywords: cyanation • enolates • boron • enantioselectivity •
synthetic methods
[1]
[2]
a) J. Schranck, M. Burhardt, C. Bornschein, H. Neumann, T. Skrydstrup,
M. Beller, Chem. Eur. J. 2014, 20, 9534; b) C. A. Malapit, D. R.
Caldwell, I. K. Luvaga, J. T. Reeves, I. Volchkov, N. C. Gonnella, Z. S.
Han, C. A. Busacca, A. R. Howell, C. H. Senanayake, Angew. Chem.
Int. Ed. 2017, 56, 6999; Angew. Chem. 2017, 129, 7103; c) K.
Kiyokawa, T. Nagata, S. Minakata, Synthesis 2018, 50, 485.
[14] a) G. P. Boldrini, F. Mancini, E. Tagliavini, C. Trombini, A. Umani-
Ronchi, J. Chem. Soc. Chem. Commun. 1990, 1680; b) G. P. Boldrini,
M. Bortolotti, E. Tagliavini, C. Trombini, A. Umani-Ronchi, Tetrahedron
Lett. 1991, 32, 1229; c) G. P. Boldrini, M. Bortolotti, F. Mancini, E.
Tagliavini, C. Trombini, A. Umani-Ronchi, J. Org. Chem. 1991, 56,
5820; d) Y. Matsumoto, T. Hayashi, Synlett 1991, 349; e) P. Nuhant, C.
Allais, W. R. Roush, Angew. Chem. Int. Ed. 2013, 52, 8703; Angew.
Chem. 2013, 125, 8865; f) C. Allais, A. S. Tsai, P. Nuhant, W. R. Roush,
Angew. Chem. Int. Ed. 2013, 52, 12888; Angew. Chem. 2013, 125,
13126.
For enantioselective conjugate addition of β-ketonitriles, see: a) T.
Morita, H. Yamada, A. Takahashi (Toa Eiyo), JP2002080444, 2002; b)
Y. Wang, X. Liu, L. Deng, J. Am. Chem. Soc. 2006, 128, 3928; c) B.
Wang, F. Wu, Y. Wang, X. Liu, L. Deng, J. Am. Chem. Soc. 2007, 129,
768; d) H. Li, J. Song, L. Deng, Tetrahedron 2009, 65, 3139; e) Y.
Kawato, N. Takahashi, N. Kumagai, M. Shibasaki, Org. Lett. 2010, 12,
1484; f) P. Chen, X. Bao, L.-F. Zhang, M. Ding, X.-J. Han, J. Li, G.-B.
Zhang, Y.-Q. Tu, C.-A. Fan, Angew. Chem. Int. Ed. 2011, 50, 8161;
Angew. Chem. 2011, 123, 8311; g) H. J. Lee, S. B. Woo, D. Y. Kim,
Tetrahedron Lett. 2012, 53, 3374; h) M.-X. Wei, C.-T. Wang, J.-Y. Du,
H. Qu, P.-R. Yin, X. Bao, X.-Y. Ma, X.-H. Zhao, G.-B. Zhang, C.-A. Fan,
Chem. Asian. J. 2013, 8, 1966; i) P. Chen, X. Bao, L.-F. Zhang, G.-J.
Liu, Y.-J. Jiang, Eur. J. Org. Chem. 2016, 704; j) K. Nakashima, Y.
Noda, S. Hirashima, Y. Koseki, T. Miura, J. Org. Chem. 2018, 83, 2402.
For enantioselective decarboxylative allylation of β-ketonitriles, see: M.
V. Vita, P. Caramenti, J. Waser, Org. Lett. 2015, 17, 5832.
[15] See the Supporting Information for details.
[16] M. J. Frisch, et al. Gaussian 09, Revision D.01.; Gaussian, Inc.:
Wallingford, CT, 2013. See the ESI for Details of the DFT calculations.
[17] S. Grimme, J. Comp. Chem. 2006, 27, 1787.
[18] A similar steric effect is proposed in the aldol reaction of an Ipc2B-
based boron enolate, see: A. Bernardi, A. M. Capelli, A. Comotti, C.
Gennari, M. Gardner, J. M. Goodman, I. Paterson, Tetrahedron 1991,
47, 3471.
[19] Construction of a chiral quarternary carbon center in an acyclic system
via the enantioselective functionalization of enolate equivalents has
been rarely reported because of the difficulties associated with the
preparation of stereodefined acyclic α,α-disubstituted enolates: a) Y.
Minko, I. Marek, Chem. Commun. 2014, 50, 12597; b) E. Haimov, Z.
Nairoukh, A. Shterenberg, T. Berkovitz, T. F. Jamison, I. Marek, Angew.
Chem. Int. Ed. 2016, 55, 5517; Angew. Chem. 2016, 128, 5607.
[3]
[4]
For reviews on enantioselective conjugate addition of α-cyano esters,
see: a) S. Jautze, R. Peters, Synthesis 2010, 365; b) M. D. Díaz-de-
Villegas, J. A. Gálvez, R. Badorrey, P. López-Ram-de-Víu, Adv. Synth.
Catal. 2014, 356, 3261.
[5]
A. H. Mermerian, G. C. Fu, Angew. Chem. Int. Ed. 2005, 44, 949;
Angew. Chem. 2005, 117, 971.
This article is protected by copyright. All rights reserved.