10.1002/anie.201713012
Angewandte Chemie International Edition
COMMUNICATION
[6]
[7]
[8]
A
notable exception are iodonium ylides, which are also neutral
similar to the barrier with catalyst 5a (26.5 kJ/mol), but markedly
lower than uncatalyzed (29.5 kJ/mol).
compounds, but carry only two substituents on the iodine center.
G. Cavallo, P. Metrangolo, R. Milani, T. Pilati, A. Priimagi, G. Resnati,
G. Terraneo, Chem. Rev. 2016, 116 (4), 2478.
In conclusion, hypervalent iodolium derivatives were
introduced as activators in a halide abstraction reaction and as
organocatalysts in a Diels-Alder benchmark reaction. For the
first time, strong indications on the crucial importance of
halogen bonding on the observed activities could be obtained
by multiple comparison experiments. These findings are in line
with previous computational studies on the importance of XB in
complexes of 3-iodanes with nucleophiles.[11] Most
importantly, by sterically blocking one or two of the electrophilic
axes, the Lewis acidity of the iodine(III) compounds could be
markedly reduced or switched off. This study thus establishes
a) L. Catalano, G. Cavallo, P. Metrangolo, G. Resnati, Halogen
Bonding in Hypervalent Iodine Compounds, in Hypervalent Chemistry.
Topics in Current Chemistry (ed T. Wirth), vol. 373, Springer, Cham
2016, pp. 289-309 b) G. Cavallo, J. S. Murray, P. Politzer, T. Pilati, M.
Ursini, G. Resnati, IUCrJ 2017, 4, 411.
[9]
G. R. Desiraju, P.S. Ho, L. Kloo, A. C. Legon, R. Marquardt, P.
Metrangolo, P. Politzer, G. Resnati, K. Rissanen, Pure Appl. Chem.
2013, 85 (8), 1711.
[10] a) D. Bulfield, S. M. Huber, Chem. Eur. J. 2016, 22 (41), 14434; b) J.-P.
Gliese, S. H. Jungbauer, S. M. Huber, Chem. Commun. 2017, 53,
12052; c) S. H. Jungbauer, S. M. Huber, J. Am. Chem. Soc. 2015, 137,
12110.
a
further class of organoiodine derivatives in XB
organocatalysis. Even though the compounds in these
experiments were monodentate, they exhibited comparably
strong activity. This relative strength as well as the unique
options associated with the two electrophilic axes offer
fascinating prospects for the further development of this class
of catalysts.
[11] For a related computational study, see: H. Pinto de Magalhães, A.
Togni, H. P. Lüthi, J. Org. Chem. 2017, 82, 11799.
[12] Y. Zhang, J. Han, Z.-J. Liu, RSC Adv. 2015, 5, 25485.
[13] a) L. Mascarelli, G. Benati, Gazz. Chim. Ital. 1908, 38, 619; b) J.
Collette, D. McGreer, R. Crawford, F. Chubb und R. B. Sandin, J. Am.
Chem. Soc. 1956, 78, 3819; c) R. C. Reynold, C. Fuson, R. L. Albright,
J. Am. Chem. Soc. 1959, 81, 487; d) P. S. Postnikov, O. A.
Guselnikova, M. S. Yusubov, A. Yoshimura, V. N. Nemykin, V. V.
Zhdankin, J. Org. Chem. 2015, 80, 5783; e) H. Xie, S. Yang, C. Zhang,
M. Ding, M. Liu, J. Guo, F. Zhang, J. Org. Chem. 2017, 82, 5250.
[14] D. Hellwinkel, G. Reiff, V. Nykodym, Liebigs. Ann. Chem. 1977, 1013.
[15] H. Tomori, J.M. Fox, S.L. Buchwald, J. Org. Chem. 2000, 65, 5334.
[16] M. Bielawski, M. Zhu, B. Olofsson, Adv. Synth. Catal. 2007, 349, 2610.
[17] N. A. Yakelis, R. G. Bergman, Organometallics 2005, 24, 3579 and
references cited therein.
Acknowledgements
The authors gratefully acknowledge support by the Fonds der
Chemischen Industrie (Dozentenstipendium to S.M.H.) and the
Cluster of Excellence RESOLV (EXC1069) by the Deutsche
Forschungsgemeinschaft.
[18] The corresponding structure of the chloride salt shows
coordination pattern: see reference [8b].
a similar
[19] A. Bondi, J. Phys. Chem. 1964, 68, 441.
Keywords: hypervalent compounds • noncovalent interactions •
halogen bonding • solvolysis • organocatalysis
[20] S. M. Walter, F. Kniep, L. Rout, F. P. Schmidtchen, E. Herdtweck, S. M.
Huber, J. Am. Chem. Soc. 2012, 134, 8507.
[21] S. M. Walter, F. Kniep, E. Herdtweck, S. M. Huber, Angew. Chem. Int.
Ed. 2011, 50, 7187.
[1]
a) T. Wirth, Hypervalent Iodine Chemistry, 1st ed., Springer-Verlag,
Berlin Heidelberg, 2003; b) A. Yoshimura, V. V. Zhdankin, Chem. Rev.
2016, 116, 3328; c) T. Dohi, Y. Kita, Hypervalent Iodine, in Iodine
Chemistry and Applications (ed T. Kaiho), John Wiley & Sons, Inc,
Hoboken, NJ, 2014, 103-157.
[22] S. H. Jungbauer, S. M. Walter, S. Schindler, L. Rout, F. Kniep, S. M.
Huber, Chem. Commun. 2014, 50, 6281.
[23] Interestingly, the methylated compound 3a is more active than the
nonmethylated one (1a) in this reaction, for currently unknown reasons.
[24] D. von der Heiden, S. Bozkus, M. Klussmann, M. Breugst, J. Org.
Chem. 2017, 82, 4037.
[2]
[3]
E. A. Merrit, B. Olofsson, Angew. Chem. Int. Ed. 2009, 48, 9052; E. A.
Merrit, B. Olofsson, Angew. Chem. 2009, 121, 9214.
a) A. P. Antonchick, S. Manna, R. Narayan, Synlett 2015, 26, 1785; b)
M. Uyanik, T. Yasui, K. Ishihara, Angew. Chem. Int. Ed. 2010, 49,
2175; c) V. V. Zhdankin, P. J. Stang, Chem. Rev. 2008, 108 (12), 5299.
a) F. V. Singh, T. Wirth, Chem. Asian. J. 2014, 9, 950; b) R. D.
Richardson, T. Wirth, Angew. Chem. Int. Ed. 2006, 45, 4402.
[25] The performance of catalyst 5b in this study was better than in the
originally published work (reference [21]), possibly due to traces of
triflate in the originally employed catalyst.
[4]
[5]
[26] CYLview, 1.0b; C. Y. Legault, Université de Sherbrooke 2009
a) E. A. Merrit, B. Olofsson, Synthesis 2011, 4, 517; b) S. V. Kohlhepp,
T. Gulder, Chem. Soc. Rev. 2016, 45, 6270; c) J. Waser, Alkynylation
with Hypervalent Iodine Reagents, in Hypervalent Iodine Chemistry (ed
T. Wirth), vol. 373, Springer, 2016, pp. 187-222; d) J. Charpentier, N.
Früh, A. Togni, Chem. Rev. 2015, 115, 650; e) K. Kiyokawa, T. Kosaka,
T. Kojima, S. Minakata, Angew. Chem. Int. Ed. 2015, 54, 13719.
[27] In the crystal structures of Figure 3, only weak contacts between the
halide and suitable hydrogen bond donating substituents of the
iodolium compounds were found (with distances of at least 95% of the
sum of the van-der-Waals radii).
This article is protected by copyright. All rights reserved.