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Journal of the American Chemical Society
Experimental procedures, characterization data (1H and 13C
NMR, HRMS, FTIR) for all new compounds (pdf). The X-ray
crystal structure data for compound 15e has been submitted to
the Cambridge Crystallographic Data Center, no. 1970101.
311+G** basis set).
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(6)
Stereochemical assignments of oxidation products were made by
analogy to 8e.
(7)
Both enantiomers of 7a*, obtained by chromatographic separa-
tion, were used for these studies (see SI). Efforts to prepare 7a* by asymmet-
ric PKR gave the product in 59% yield and 72% ee ([RhCl(CO)2]2, (R)-
BINAP, PhMe, CO, 90 °C). See: Furusawa, T.; Morimoto, T.; Ikeda, K.;
Tanimoto, H.; Nishiyama, Y.; Kakiuchi, K.; Jeong, N. Asymmetric Pauson–
Khand-Type reactions of 1,6-enynes using formaldehyde as a carbonyl
source by cooperative dual rhodium catalysis. Tetrahedron 2015, 71, 875.
AUTHOR INFORMATION
Corresponding Author
*reisman@caltech.edu
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(a) Sharpless, K. B.; Lauer, R. F. Selenium Dioxide Oxidation of
AUTHOR CONTRIBUTIONS
‡These authors contributed equally to this work and are
listed alphabetically.
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Olefins. Evidence for the Intermediacy of Allylseleninic Acids. J. Am. Chem.
Soc. 1972, 94, 7154. (b) Arigoni, D.; Vasella, A.; Sharpless, K. B.; Jensen, H.
P. Selenium Dioxide Oxidations of Olefins. Trapping of the Allylic Seleninic
Acid Intermediate as a Seleninolactone. J. Am. Chem. Soc. 1973, 95, 7917.
(c) Młochowski, J; Wójtowicz-Młochowska, H. Developments in Synthetic
Application of Selenium(IV) Oxide and Organoselenium Compounds as
Oxygen Donors and Oxygen-Transfer Agents. Molecules 2015, 20, 10205.
ACKNOWLEDGMENT
We thank Dr. Michael Takase and Larry Henling (both of Caltech) for
X-ray data collection and Dr. Julie Hofstra (Caltech) for X-ray data re-
finement. Dr. Scott Virgil and the Caltech Center for Catalysis and
Chemical Synthesis are gratefully acknowledged for access to analytical
equipment. Fellowship support was provided by the NSF (S. E. D., M.
R. M. Grant No. DGE-1144469). S.E.R. is a Heritage Medical Research
Institute Investigator. Financial support from the NIH
(R35GM118191-01) is acknowledged.
(9)
The structure of 12a was determined by 1H, 13C, and HSQC
NMR (see SI). (a) Riley, H. L.; Morley, J. F.; Friend, N. A. C. Selenium Di-
oxide, a New Oxidising Agent. Part I. Its Reaction with Aldehydes and Ke-
tones. J. Chem. Soc. 1932, 1875. (b) Sharpless, K. B.; Gordon, K. M. Sele-
nium Dioxide Oxidation of Ketones and Aldehydes. Evidence for the Inter-
mediacy of b-Ketoseleninic Acids. J. Am. Chem. Soc. 1976, 98, 300. For ex-
amples of Riley oxidation in synthesis, see: (c) Mehta, G., Shinde, H. M. En-
antiospecific total synthesis of 6-epi-(-)-hamigeran B. Intramolecular Heck
reaction in a sterically constrained environment. Tetrahedron Lett. 2003, 44,
7049. (d) Trost, B. M.; Pissot-Soldermann, C.; Chen, I.; Schroeder, G. M.
An asymmetric synthesis of hamigeran B via a Pd asymmetric allylic alkyla-
tion for enantiodiscrimination. J. Am. Chem. Soc. 2004, 126, 4480. (e) Con-
dakes, M. L.; Hung, K.; Harwood, S. J.; Maimone, T. J. Total Syntheses of
(−)-Majucin and (−)-Jiadifenoxolane A, Complex Majucin-Type Illicium
Sesquiterpenes. J. Am. Chem. Soc. 2017, 139, 17783.
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(1)
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(10) For precedent of an analogous intramolecular oxy-Michael addi-
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(2)
(a) Shibata, T. Recent Advances in the Catalytic Pauson–Khand-
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(12) Because an intermediate analogous to 12a was not observed dur-
ing the oxidation of substrates without γ-substitution (7a-g), further appli-
cation of this protocol is limited.
(a) Littke, A. F.; Dai, C.; Fu, G. C. Versatile Catalysts for the Suzuki Cross-
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(3)
(a) Chuang, K. V.; Xu, C.; Reisman, S. E. A 15-Step Synthesis of
(+)-Ryanodol. Science 2016, 353, 912. (b) Xu, C.; Han, A.; Virgil, S. C.; Reis-
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(4)
The use of fewer equiv SeO2 (1.5 or 3.0) proved to be less gen-
eral (see SI), thus the conditions of entry 3 were selected as optimal for in-
vestigating the scope of the dioxidation reaction.
(5)
The trans-fused isomer of 8a was calculated to be 18.5 kcal/mol
less stable (calculated using Spartan’14, Hartree-Fock model using the 6-
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