Page 9 of 9
Organic & Biomolecular Chemistry
Please do not adjust margins
Journal Name
ARTICLE
presence of nucleophilic phosphines provide insight into
competing reaction pathways and their relative rates. With the
better understanding of these pathways, selectivity in related
reactions can be controlled by external factors, i.e. by protic
additives.
Ashley, Chem. Soc. Rev. 2017, 46, 5689-5700.
DOI: 10.1039/C8OB01343H
[8]
Frustrated Lewis pairs are systems of sterically hindered Lewis donors and
acceptors where steric demands preclude formation of simple Lewis acid–
base adducts, allowing for the subsequent actions of both Lewis acids and
bases on other molecules. They are typically seen as a combination of a
bulky Lewis base and a very strong, bulky Lewis acid (a common example
is B(C6F5)3). PBu3 and pinBH do not traditionally fit this definition, yet they
do not form classical Lewis acid–base adducts which is why we refer to
this system as a non-traditional frustrated Lewis pair.
Conflicts of interest
There are no conflicts to declare.
[9]
Hydroboration reactions are typically syn functionalization of unsaturated
compounds which proceed with suprafacial delivery of hydrogen and boron
to the same π-face of the starting material. Although the opposite
stereochemical outcome could be termed anti, the implication of the term
anti is that the hydrogen and boron atoms are simultaneously delivered to
the opposite faces of the π-system. For this reason, we prefer the term
trans-hydroboration which carries no mechanistic implications and
accurately describes stereochemical outcome of the described process. In
addition to stereoisomers, hydroboration of differentially substituted
alkynes can lead to different regioisomers too.
Acknowledgements
Financial support from the Carl-Zeiss Foundation (endowed pro-
fessorship to I.V.) and Friedrich Schiller University Jena is grate-
fully acknowledged.
[10] K. D. Collins, F. Glorius, Nature Chem. 2013, 5, 597-601.
[11] a) S. Espenlaub, H. Gerster, G. Maas, ARKIVOC 2007, 114-131; b) S. E.
Denmark, G. L. Beutner, Angew. Chem. Int. Ed. 2008, 47, 1560-1638.
[12] Y. Wu, C. Shan, J. Ying, J. Su, J. Zhu, L. L. Liu, Y. Zhao, Green Chem.
2017, 19, 4169-4175.
Notes and references
[1]
a) C. C. Chong, R. Kinjo, ACS Catal. 2015, 5, 3238-3259; b) S. Itsuno,
ACS Sym. Ser. 2016, 1236, 241-274; c) F. Chen, Y. Zhang, L. Yu, S. Zhu,
Angew. Chem. Int. Ed. 2017, 56, 2022-2025; d) V. Vasilenko, C. K. Blasius,
H. Wadepohl, L. H. Gade, Angew. Chem. Int. Ed. 2017, 56, 8393-8397; e)
Z. Zhang, P. Jain, J. C. Antilla, Angew. Chem. Int. Ed. 2011, 50, 10961-
10964; f) M. R. Adams, C.-H. Tien, B. S. N. Huchenski, M. J. Ferguson, A.
W. H. Speed, Angew. Chem. Int. Ed. 2017, 56, 6268-6271; g) A. Ford, S.
Woodward, Angew. Chem. Int. Ed. 1999, 38, 335-336; h) A. J. Blake, A.
Cunningham, A. Ford, S. J. Teat, S. Woodward, Chem. Eur. J. 2000, 6,
3586-3594; i) I. P. Query, P. A. Squier, E. M. Larson, N. A. Isley, T. B. Clark,
J. Org. Chem. 2011, 76, 6452-6456.
[13] During preparation of this manuscript, similar work was published by the
groups of Sawamura and Ohmiya: K. Nagao, A. Yamazaki, H. Ohmiya, M.
Sawamura Org. Lett. 2018, 7, 1861-1865. Although similar to our work on
trans-hydroboration, this report describes hydroboration of ynoates in THF
at elevated temperatures. While trans-hydroboration or ynoates seems to
be tolerant of different solvents, 1,2-reduction of ynones specifically
requires solvents that do not activate pinacolborane via formation of Lewis
pairs (decrease of both regio- and chemoselectivity of reductions in THF,
diethyl ether or dioxane have been observed in our previous study). The
hydroboration reactions of ynoates in dichloromethane at room
temperature and in dichloroethane at elevated temperature, presented
here, enable a sound comparison of the two methods.
[2]
a) H. C. Brown, S. K. Gupta, J. Amer. Chem. Soc. 1972, 94, 4370-4371;
b) H. C. Brown, S. K. Gupta, J. Am. Chem. Soc. 1975, 97, 5249-5255; c)
K. Semba, T. Fujihara, J. Terao, Y. Tsuji, Chem. Eur. J. 2012, 18, 4179-
4184; d) J. V. Obligacion, J. M. Neely, A. N. Yazdani, I. Pappas, P. J. Chirik,
J. Am. Chem. Soc. 2015, 137, 5855-5858; e) A.-M. Carroll, T. P. O'Sullivan,
P. J. Guiry, Adv. Synth. Catal. 2005, 347, 609-631; f) X. He, J. F. Hartwig,
J. Am. Chem. Soc. 1996, 118, 1696-1702; g) J. S. McGough, S. M. Butler,
I. A. Cade, M. J. Ingleson, Chem. Sci. 2016, 7, 3384-3389.
[14] W. Santos, C. Peck, J. Calderone, Synthesis 2015, 47, 2242-2248.
[15] Several methods have been developed for trans-hydroboration of terminal
alkynes: a) J. Cid, J. J. Carbo, E. Fernandez, Chem. Eur. J. 2012, 18, 1512-
1521; b) W. J. Jang, W. L. Lee, J. H. Moon, J. Y. Lee, J. Yun, Org. Lett.
2016, 18, 1390-1393; (c) T. Ohmura, Y. Yamamoto, N. Miyaura, J. Am.
Chem. Soc. 2000, 122, 4990-4991; (d) C. Gunanathan, M. Hoelscher, F.
Pan, W. Leitner, J. Am. Chem. Soc. 2012, 134, 14349-14352. and
references 2d and 2g. Some of these involve a rearrangement which
ultimately positions the proton of a terminal alkyne in trans-position to the
boron (the borane hydrogen and boron are connected to the same carbon
in the product).
[3]
a) Z. M. Heiden, A. P. Lathem, Organometallics 2015, 34, 1818-1827; b) I.
E. Golub, O. A. Filippov, E. S. Gulyaeva, E. I. Gutsul, N. V. Belkova, Inorg.
Chim. Acta 2017, 456, 113-119; c) M. Horn, L. H. Schappele, G. Lang-
Wittkowski, H. Mayr, A. R. Ofial, Chem. Eur. J. 2013, 19, 249-263.
P. V. Ramachandran, J. S. Chandra, A. Ros, R. Fernandez, J. M.
Lassaletta, John Wiley & Sons, Ltd., 2014, pp. 1-7.
[4]
[5]
a) S. Shimada, A. S. Batsanov, J. A. K. Howard, T. B. Marder, Angew.
Chem. Int. Ed. 2001, 40, 2168-2171; b) D. Noh, H. Chea, J. Ju, J. Yun,
Angew. Chem. Int. Ed. 2009, 48, 6062-6064; c) S. Pereira, M. Srebnik,
Organometallics 1995, 14, 3127-3128; d) K. L. Billingsley, S. L. Buchwald,
J. Org. Chem. 2008, 73, 5589-5591; e) J. Y. Wu, B. Moreau, T. Ritter, J.
Am. Chem. Soc. 2009, 131, 12915-12917; f) M. Murata, T. Oyama, S.
Watanabe, Y. Masuda, J. Org. Chem. 2000, 65, 164-168; g) J.-Y. Cho, M.
K. Tse, D. Holmes, R. E. Maleczka, Jr., M. R. Smith, III, Science 2002, 295,
305-308; h) J. F. Hartwig, K. S. Cook, M. Hapke, C. D. Incarvito, Y. Fan,
C. E. Webster, M. B. Hall, J. Am. Chem. Soc. 2005, 127, 2538-2552; i) S.
Pereira, M. Srebnik, Tetrahedron Lett. 1996, 37, 3283-3286.
[16] a) B. Sundararaju, A. Fürstner, Angew. Chem. Int. Ed. 2013, 52, 14050-
14054; b) L.-J. Song, T. Wang, X. Zhang, L. W. Chung, Y.-D. Wu, ACS
Catal. 2017, 7, 1361-1368.
[17] a) K. Yuan, N. Suzuki, S. K. Mellerup, X. Wang, S. Yamaguchi, S. Wang,
Org. Lett. 2016, 18, 720-723; b) Y. Yang, J. Jiang, H. Yu, J. Shi, Chem.
Eur. J. 2018, 24, 178-186; c) S. Xu, Y. Zhang, B. Li, S.-Y. Liu, J. Am. Chem.
Soc. 2016, 138, 14566-14569.
[18] a) K. Nagao, H. Ohmiya, M. Sawamura, Org. Lett. 2015, 17, 1304-1307;
b) K. Nagao, H. Ohmiya, M. Sawamura, J. Am. Chem. Soc. 2014, 136,
10605-10608; c) H. Murayama, K. Nagao, H. Ohmiya, M. Sawamura, Org.
Lett. 2016, 18, 1706-1709.
[6]
[7]
F. Schomberg, Y. Zi, I. Vilotijevic, Chem. Commun. 2018, 54, 3266-3269.
a) D. W. Stephan, G. Erker, Angew. Chem. Int. Ed. 2015, 54, 6400-6441;
b) D. W. Stephan, Acc. Chem. Res. 2015, 48, 306-316; c) J. S. McCahill,
G. C. Welch, D. W. Stephan, Angew. Chem. Int. Ed. 2007, 46, 4968-4971;
d) G. C. Welch, L. Cabrera, P. A. Chase, E. Hollink, J. D. Masuda, P. Wei,
D. W. Stephan, Dalton Trans. 2007, 3407-3414; e) P. A. Chase, D. W.
Stephan, Angew. Chem. Int. Ed. 2008, 47, 7433-7437; f) M. A. Dureen, A.
Lough, T. M. Gilbert, D. W. Stephan, Chem. Commun. 2008, 4303-4305;
g) D. W. Stephan, G. Erker, Angew. Chem. Int. Ed. 2010, 49, 46-76; h) D.
[19] Y. Li, G. Liu, C. Cao, S. Wang, Y. Li, G. Pang, Y. Shi, Tetrahedron 2013,
69, 6241-6250.
[20] J. J. Molloy, J. B. Metternich, C. G. Daniliuc, A. J. B. Watson, R. Gilmour,
Angew. Chem. Int. Ed. 2018, 57, 3168-3172.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 9
Please do not adjust margins