Journal of the American Chemical Society
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3822-3863. (e) Lelais, G.; MacMillan, D. W. C. Aldrich Chim. Acta
CONCLUSION
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Am. Chem. Soc. 2002, 124, 9992-9993.
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1498-1499.
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Enhancement of enantioselective catalysis of Diels–Alder
reactions by introduction of fluorine substituents in oxa-
zaborolidinium cations has been demonstrated as both
significant and useful. Specifically, the objective of achiev-
ing excellent reaction rates, product yields and enantiose-
lectivities has been realized using 1–2 mol% of several
catalysts e.g. F2/F0, F2/F2 and F7/F0 structures. The
chiral prolinols used for catalysis are readily prepared and
easily recovered for reuse (see Supporting Information). A
variety of specific examples document some of the many
ways in which readily available chiral Diels–Alder adducts
can be used either for general synthesis or for the produc-
tion of chiral ligands and reagents that are useful for
asymmetric catalysis. Efficient synthetic procedures have
been presented for each of the new second generation
chiral ligands and precatalysts (see Supporting Infor-
mation).
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8160-8161.
(13) Ryu, D. H.; Corey, E. J. J. Am. Chem. Soc. 2004, 126, 8106-
ASSOCIATED CONTENT
8107.
Experimental procedures and characterization data for all
reactions and products including copies of H and 13C NMR
1
(14) Hu, Q.-Y.; Rege, P. D.; Corey, E. J. J. Am. Chem. Soc. 2004,
126, 5984-5986.
(15) Yeung, Y.-Y.; Hong, S.; Corey, E. J. J. Am. Chem. Soc. 2006,
spectra. This material is available free of charge via the Inter-
128, 6310-6311.
(16) Hu, Q.-Y.; Zhou, G.; Corey, E. J. J. Am. Chem. Soc. 2004,
126, 13708-13713.
(17) Hong, S.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 1346-
1352.
(18) Snyder, S. A.; Corey, E. J. J. Am. Chem. Soc. 2006, 128, 740-
742.
AUTHOR INFORMATION
Corresponding Author
*corey@chemistry.harvard.edu
Notes
The authors declare no competing financial interest.
(19) (a) Paddon-Row, M. N.; Kwan, L. C. H.; Willis, A. C.;
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(20) For recent reviews of the inductive effects of β-F on
amine properties see (a) Morgenthaler, M.; Schweizer, E.; Hoff-
mann-Röder, A.; Benini, F.; Martin, R. E.; Jaeschke, G.; Wagner,
B.; Fischer, H.; Bendels, S.; Zimmerli, D.; Schneider, J.; Diederich,
F.; Kansy. M.; Müller, K. Chem. Med. Chem. 2007, 2, 1100-1115. (b)
Müller, K.; Faeh, C.; Diederich, F. Science 2007, 317, 1881-1886. (c)
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(22) (a) Shevchenko, N. E.; Nenajdenko, V. G.; Röschenthaler,
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pounds Roesky, H. W., Ed.; J. Wiley and Sons, Hoboken, 2013, p
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(23) (a) White, J. D.; Shaw, S. Org. Lett. 2011, 13, 2488-2491. (b)
White, J. D.; Shaw, S. Org. Lett. 2012, 14, 6270-6273. (c) White, J.
D.; Shaw, S. Org. Lett. 2014, 16, 3880-3883. (d) White, J. D.; Shaw,
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ACKNOWLEDGMENT
We are grateful to the following for research grants: Pfizer,
Gilead, Bristol-Myers Squibb and Strategic Science and
Technology. S. B. acknowledges a postdoctoral fellowship
from the Swiss National Science Foundation. We were gen-
erously supplied with Deoxo–Fluor by Airgas Co. and pen-
tafluoroethane by DuPont/Chemours. We thank Dr. Shao-
Liang Zheng for his help with the X-ray data collection and
structure determination.
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