Organic Letters
Letter
Bernhard, S.; Tantillo, D. J.; Brummond, K. M. J. Org. Chem. 2015, 80,
11686. (d) Ozawa, T.; Kurahashi, T.; Matsubara, S. Org. Lett. 2011, 13,
5390.
(9) Certain reactions involving ynamides are postulated to proceed via
dearomatized cyclic allenes under some conditions; see: (a) Martínez-
ASSOCIATED CONTENT
* Supporting Information
TheSupportingInformationisavailablefreeofchargeontheACS
■
S
Esperon
2213. (b) Rodríguez, D.; Castedo, L.; Domínguez, D.; Saa,
2004, 2004, 761.
́
, M. F.; Rodríguez, D.; Castedo, L.; Saa,
́
C. Org. Lett. 2005, 7,
Experimental procedures, spectroscopic characterization
data, copies of 1H and 13C NMR spectra (PDF)
Crystallographic data for 28 (CIF)
́
C. Synthesis
(10) Alkyne π-bonds are stronger than alkene π-bonds, which can
translate into larger activation barriers for reactions that break those π-
bonds; see: Nicolaides, A.; Borden, W. T. J. Am. Chem. Soc. 1991, 113,
6750.
(11) (a) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. J. Chem. Soc., Trans.
1915, 107, 1080. (b) Curtin, M. L.; Okamura, W. H. J. Org. Chem. 1990,
55, 5278.
(12) Trost, B. M.; Bridges, A. J. J. Am. Chem. Soc. 1976, 98, 5017.
(13) Hoang, T. T.; Dudley, G. B. Org. Lett. 2013, 15, 4026.
(14) Production here of electron-rich alkenes represents an important
conceptual expansion of our previously reported tandem fragmentation/
olefination methodology (ref 12), which exclusively produced electron-
deficient alkenes.
AUTHOR INFORMATION
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Corresponding Author
Notes
The authors declare no competing financial interest.
The CIF for compound 28 file can be downloaded via the CCDC
citing structure number 1486383.
ACKNOWLEDGMENTS
■
This research was supported by a grant from the National Science
Foundation (NSF-CHE 1300722) and by the FSU Department
of Chemistry and Biochemistry. We thank Tristan Dilbeck
(Hanson Lab, FSU) for assistance with absorption and emission
measurements and Ken Hanson (FSU) and Mike Shatruk (FSU)
for helpful discussions.
(16) We do not invoke any concerted intramolecular hydride shifts in
our mechanistic hypotheses.
(17) The four benzylic methylene hydrogens in the 1H NMR spectrum
of 4 appear as a singlet that integrates to 4.0 hydrogens. The
corresponding singlet in the 1H NMR spectrum of 4-d integrates to 3.6
hydrogens, which we interpret as 40% deuterium incorporation.
Subjecting 4 to these same conditions results in no more than 10%
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