Organic Letters
Letter
coupling constants of 1.6 and 9.4 Hz; the C-10 proton resonance of
10 at 3.69 ppm (doublet) displayed a coupling constant of 2.0 Hz.
These data are indicative of the β-configuration at C-5′; see ref 16b
and Procko, K. J.; Li, H.; Martin, S. F. Org. Lett. 2010, 12, 5632.
(b) We attempted chromatographic separation (SiO2) of the C-10
diastereomers of compound 11 (as well as later compounds 17 and
18) but were unsuccessful. Since the diastereomers lead to different
natural products, we proceeded with the mixtures until adequate
chromatographic resolution could be achieved at the natural product
stage, as indicated in the original isolation papers (ref 1).
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the
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S
Detailed experimental procedures including spectro-
scopic and analytical data (PDF)
AUTHOR INFORMATION
(15) Zhao, M.; Li, J.; Mano, E.; Song, Z.; Tschaen, D. M.;
Grabowski, E. J. J.; Reider, P. J. J. Org. Chem. 1999, 64, 2564.
(16) (a) Sheldon, R. A.; Kochi, J. K. Org. React. 1972, 19, 279. (b)
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Corresponding Author
ORCID
1
The C-1′ proton resonance in the H NMR spectrum of compound
14 (CDCl3) at 5.98 ppm (doublet) displayed a coupling constant of
2.4 Hz; C.1′ coupling constants of a similar magnitude were measured
for compounds 17 and 18. These data are indicative of the α-
configuration at C.1′. See: Karplus, M. J. Am. Chem. Soc. 1963, 85,
2870.
Notes
(17) Lohman, G. J. S.; Seeberger, P. H. J. Org. Chem. 2004, 69, 4081.
(18) (a) Toshima, K.; Tatsuta, K. Chem. Rev. 1993, 93, 1503.
(b) Schmidt, R. R.; Castro-Palomino, J. J.; Retz, O. Pure Appl. Chem.
1999, 71, 729.
(19) Conway, S. J.; Gardiner, J.; Grove, S. J. A.; Johns, M. K.; Lim,
Z.-Y.; Painter, G. F.; Robinson, D. E. J. E.; Schreiber, C.; Thuring, J.
W.; Wong, L. S.-M.; Yin, M.-X.; Burgess, A. W.; Catimel, B.; Hawkins,
P. T.; Ktistakis, N. T.; Stephens, L. R.; Holmes, A. B. Org. Biomol.
Chem. 2010, 8, 66.
(20) Hacksell, U.; Daves, G. D. Prog. Med. Chem. 1985, 22, 1.
(21) Wilson, W. D.; Tanious, F. A.; Fernandez-Saiz, M.; Rigl, C. T.
Methods in Mol. Biol. Drug-DNA Interact. Protoc. 1997, 90, 219.
(22) Morgan, A. R.; Lee, J. S.; Pulleyblank, D. E.; Murray, N. L.;
Evans, D. H. Nucleic Acids Res. 1979, 7, 547.
(23) Wei, A.; Boy, K. M.; Kishi, Y. J. Am. Chem. Soc. 1995, 117,
9432.
(24) Liu, C.; Liu, Z.; Wang, J. PLoS One 2017, 12, No. e0176208.
(25) Chatterjee, T.; Pal, A.; Dey, S.; Chatterjee, B. K.; Chakrabati, P.
PLoS One 2012, 7, No. e37468.
(26) Na, N.; Zhao, D.-Q.; Li, H.; Jiang, N.; Wen, J.-Y.; Liu, H.-Y.
Molecules 2016, 21, 54.
(27) Callies, O.; Hernandez Daranas, A. Nat. Prod. Rep. 2016, 33,
881.
(28) Sudlow, G. D. J. B.; Birkett, D. J.; Wade, D. N. Mol. Pharmacol.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
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We acknowledge the National Science Foundation (CHE-
1508070) and the donors of the American Chemical Society
Petroleum Research Fund (53693-URI) for their generous
support of this research. We thank the UCR mass spectrometry
facility for accurate mass determinations.
REFERENCES
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(1) (a) Mi, Q.; Lantvit, D.; Reyes-Lim, E.; Chai, H.; Phifer, S. S.;
Wani, M. C.; Wall, M. E.; Tan, G. T.; Cordell, G. A.; Farnsworth, N.
R.; Kinghorn, A. D.; Pezzuto, J. M. Anticancer Res. 2005, 25, 779.
(b) Phifer, S. S.; Lee, D.; Seo, E.-K.; Kin, N.-C.; Graf, T. N.; Kroll, D.
J.; Navarro, H. A.; Izydore, R. A.; Jimenez, F.; Garcia, R.; Rose, W. C.;
Fairchild, C. R.; Wild, R.; Soejart, D. D.; Farnsworth, N. R.; Kinghorn,
D.; Overlies, N. H.; Wall, M. E.; Wani, M. C. J. Nat. Prod. 2007, 70,
954.
(2) Hernandez-Medel, M.; Garcia-Salmones, I.; Snatillan, R.; Trigos,
A. Phytochemistry 1998, 49, 2599.
(3) Hernandez-Medel, M.; Pereda-Miranda, R. Planta Med. 2002,
68, 556.
(4) Koyama, Y.; Yamaguchi, R.; Suzuki, K. Angew. Chem., Int. Ed.
2008, 47, 1084.
(5) Crich, D.; Sasaki, K. The Hunsdiecker and Related Reactions. In
Comprehensive Organic Synthesis; Knochel, P., Molander, G. A., Eds.;
Pergamon Press: Oxford, 2014; Vol. 7, pp 818−836.
(6) (a) Kitamura, K.; Ando, Y.; Matsumoto, T.; Suzuki, K. Chem.
Rev. 2018, 118, 1495. (b) Yang, Y.; Yu, B. Chem. Rev. 2017, 117,
12281.
(7) (a) Zhu, F.; Rodriguez, J.; O’Neill, S.; Walczak, M. A. ACS Cent.
Sci. 2018, 4, 1652. (b) Yi, D.; Zhu, F.; Walczak, M. A. Org. Lett. 2018,
20, 4627. (c) Koester, D. C.; Leibeling, M.; Neufeld, R.; Werz, D. B.
Org. Lett. 2010, 12, 3934. (d) Koester, D. C.; Kriemen, E.; Werz, D. B.
Angew. Chem., Int. Ed. 2013, 52, 2985. (e) Mabit, T.; Siard, A.; Legros,
F.; Guillarme, S.; Martel, A.; Lebreton, J.; Carreaux, F.; Dujardin, G.;
Collet, S. Chem. - Eur. J. 2018, 24, 14069.
1976, 12, 1052.
(29) Though the NMR spectra of the natural products were
originally recorded in (CD3)2CO, we found that significant degrees of
epimerization of the separated compounds 1−4 occurred in this
solvent. In contrast, much less epimerization was observed in CDCl3.
For this reason, and to be consistent, 1H NMR and 13C NMR data for
the separated compounds 1−4 were recorded in CDCl3 (see
(8) Postema, M. H. D.; Piper, J. L.; Komandui, V.; Liu, L. Angew.
Chem., Int. Ed. 2004, 43, 2915.
(9) Sodeoka, M.; Hirai, G.; Watanabe, T.; Mayagi, T. Pure Appl.
Chem. 2009, 81, 205.
(10) Kiya, N.; Hidaka, Y.; Usui, K.; Hirai, G. Org. Lett. 2019, 21,
1588.
(11) Schaltegger, A.; Steiger, W. Arch. Pharm. 1986, 319, 575.
(12) Ciuffreda, P.; Ronchetti, F.; Lucio, T. J. Carbohydr. Chem. 1989,
8, 805.
(13) Nashed, M. A.; Laurens, A. Carbohydr. Res. 1976, 51, 65.
1
(14) (a) The C-5′ proton resonance in the H NMR spectrum of
compound 10 (CDCl3) at 3.50 ppm (doublet of doublets) displayed
D
Org. Lett. XXXX, XXX, XXX−XXX