N. Galy et al. / Tetrahedron Letters 51 (2010) 695–697
697
11. This substance is dangerous and may burn or explode on contact with air, see:
(a) Bashford, L. A.; Emeleus, H. J.; Briscoe, H. V. A. J. Chem. Soc. 1938, 1358–
1364; (b) Tanaka, R.; Miller, S. I. J. Org. Chem. 1971, 36, 3856–3861.
12. Krikorian, S. E., PhD, Massachusetts Institute of Technology (USA), 1967.
13. (a) Kassaee, M. Z.; Ghavami, M.; Vessaly, E.; Chehmehkani, A. Asian J. Chem.
2009, 21, 1365–1371; (b) Toulouse, J.; Umrigar, C. J. J. Chem. Phys. 2007, 126,
084102–084116.
14. Bytautas, L.; Ruedenberg, K. J. Chem. Phys. 2005, 122, 154110–154121.
15. (a) Douay, M.; Nietmann, R.; Bernath, P. F. J. Mol. Spectrosc. 1988, 131, 250–260;
(b) Cade, P. E.; Wahl, A. C. Data Nucl. Data Tables 1974, 13, 340.
16. (a) Becke, A. D. J. Chem. Phys. 1993, 98, 5648–5652; (b) Lee, C.; Yang, W.; Parr, R.
G. Phys. Rev. B 1988, 37, 785–789.
2
3
−
−
C3 = 1.406 Å
Bond lengths: C1
C
2 = 1.377 Å; C2
1
7
−
Mulliken atomic spin densities: C1 : 0.667; C2 : 0.321; C3 : 0.687
2
C
1
C
− −
Bond lengths: C C = 1.1994 Å; C H = 1.0627 Å
H
8
−
: 0.402; H : 0.019
Mulliken atomic spin densities : C1 : 1.382; C2
Figure 1. Structure of the 2,3,3-trimethylallylic radical 7 and ethynyl 8 at the
B3LYP/6.311G(3df,3pd) level of theory.
17. Møller, C.; Plesset, M. S. Phys. Rev. 1934, 46, 618–622.
18. Frisch, M. J. et al GAUSSIAN, Revision E.01; Gaussian: Pittsburgh, PA, 2004.
19. Warning, in the absence of cyclohexene, the reaction of 1,2-dibromoethylene
with potassium tert-butoxide led to pyrophoric and explosive products.
20. Leber, P. A.; Bogdan, A. R.; Powers, D. C.; Baldwin, J. E. Tetrahedron 2007, 63,
6331–6338.
Table 2
Calculations at the B3LYP/6.311G(3df,3pd) level of intermediates of the hydrogen
atom exchange reaction between C2 molecule 6 and 2,3-dimethyl-2-butene 5
21. Ma, S.; Ni, B.; Lin, S.; Liang, Z. J. Organomet. Chem. 2005, 690, 5389–5395.
22. Dang, H. S.; Davies, A. G. J. Chem. Soc., Perkin Trans. 2 1991, 2011–2020.
23. Rodgers, A. S.; Wu, M. C. R. J. Am. Chem. Soc. 1973, 95, 6913–6917.
24. A 250 mL, three-necked flask was equipped with a motor-driven stirrer passing
through a bushing in the central neck, an argon inlet, and a septum. It was
charged with potassium tert-butoxide (38 g, 335 mmol, 2.5 equiv) in 2,3-
dimethyl-2-butene (100 mL, 830 mmol) and pentane (50 mL), and was cooled
to ꢀ60 °C. Then, 1,2-dibromoethylene (cis and trans) (25 g, 134 mmol) was
slowly added with a syringe. Gradually, the suspension became jelly. After 3 h,
the temperature was warmed to ꢀ40 °C for 18 h, ꢀ20 °C for 5 h, and 0 °C for
24 h. Progressively, the solution became fluid. Then, solid NH4Cl was added to
the reaction mixture, stirred for 15 min followed by addition of crushed ice.
After decantation, the aqueous layer was extracted with pentane. The organic
phases were washed with water and dried over MgSO4. The solvent was
removed by distillation (bath temperature <60 °C, caution, the first fractions of
the distillation contains bromoacetylene), and the crude product was flash
chromatographed on silica gel (pentane–diethyl ether 99:1 to 70:30) to give a
mixture of 5 and dibromoacetylene and then a mixture of 10 with 11 in some
cases.
Compound
Energy (hartree)
D
G (hartree)
dDG (kcal/mol)
5
7
ꢀ235.938832
–235.297561
–75.942339
–76.636177
–235.807528
–235.180554
–75.957912
–76.642727
393.4
–429.7
C2 molecule, 6
Ethynyl, (C2H), 8
3. Conclusion
Calculations do not give a valuable response concerning the
state, singlet, or triplet of the C2 molecule. Our results have clearly
shown that, in solution this species reacts as a diradical which is
stabilized by hydrogen abstraction. However, we do not detect
the formation of butadiyne.
25. Griesbeck, A. G.; Cho, M. Org. Lett. 2007, 9, 611–613.
Acknowledgments
26. To a 2 mL syringe containing a wad of cotton, a layer of silica gel topped by a
layer of CeliteÒ was added 0.75 mL of crude product. After filtration, the
obtained colorless liquid was added to a very small quantity of CDCl3 and then
the NMR spectra was immediately recorded (Bruker AC300 spectrometer).
27. Jackowski, K.; Gryff-Keller, A.; Sas, W.; Szczecinski, P. Pol. J. Chem. 1996, 70,
221–230.
N.G. is grateful to the CNRS and the Région Provence-Alpes-Côte
d’Azur for a grant. This work has been financially supported by
the CNRS and the Ministère de l’Education Nationale.
28. Dibromoacetylene: acetylene was bubbled through
a stirred solution of
aqueous potassium hypobromide. Butadiyne results from an elimination
reaction of 1,4-dichloro-2-butyne according to: Solladié, G.; Somny, F.;
Colobert, F. Tetrahedron: Asymmetry 1997, 8, 801–810.
References and notes
1. (a) Páramo, A.; Canosa, A.; Le Picard, S. D.; Sims, I. R. J. Phys. Chem. A 2006, 110,
3121–3127. and references therein; b Dyrka, M.; Wszolek, B.; Pawlikowski, M.
Los Alamos National Laboratory, Preprint Archive, Astrophysics, 2006.
2. (a) Skell, P. S.; Harris, R. F. J. Am. Chem. Soc. 1966, 88, 5933–5934; (b) Skell, P. S.;
Plonka, J. H. J. Am. Chem. Soc. 1970, 92, 5620–5624.
3. Zavitsanos, P. D.; Carlson, G. A. J. Chem. Phys. 1973, 59, 2966–2973.
4. Gusarov, A. V.; Titov, V. I.; Scharff, W. J. Phys. D: Appl. Phys. 2005, 38, 2881–2889.
5. Drowart, J.; Burns, R. P.; DeMaria, G.; Inghram, M. G. J. Chem. Phys. 1959, 31, 1131–
1132.
6. Kruse, T.; Roth, P. High-temperature Reaction of C2 with Atomic and Molecular
Oxygen in 27th Symp. (Int.) on Combustion; The Combustion Institute:
Pittsburgh, 1998.
7. Klein-Douwel, R. J. H.; Spaanjaars, J. J. L.; ter Meulen, J. J. J. App. Phys. 1995, 78,
2086–2096.
8. (a) Dolbier, W. R.; Akiba, K. Y.; Bertrand, M.; Bezaguet, A.; Santelli, M. J. Chem.
Soc., Chem. Commun. 1970, 717–718; (b) Dolbier, W. R.; Akiba, K. Y.; Riemann, J.
M.; Harmon, C. A.; Bertrand, M.; Bezaguet, A.; Santelli, M. J. Am. Chem. Soc.
1971, 93, 3933–3940.
9. (a) Loosli, T.; Borer, M.; Kulakowska, I.; Minger, A.; Neuenschwander Helv.
Chim. Acta 1995, 78, 1144–1165; (b) de Meijere, A.; Kozhushkov, S. I. Eur. J. Org.
Chem. 2000, 3809–3822.
10. (a) Skell, P. S.; Wescott, L. D., Jr.; Golstein, J.-P.; Engel, R. R. J. Am. Chem.
Soc. 1965, 87, 2829–2835; (b) Den Besten, I. E.; Wenger, C. R. J. Am. Chem.
Soc. 1970, 92, 5620–5624; See also: Cataldo, F. Tetrahedron Lett. 2004, 45,
141–144.
29. (a) Yokota, M.; Koyama, R.; Hayashi, H.; Uchibori, S.; Tomiyama, T.; Miyazaki,
H. Synthesis 1994, 1418–1428; (b) Nishio, T. J. Chem. Soc., Perkin Trans. 1 1991,
1717–1720.
30. Dang, H.-S.; Davies, A. G.; Davison, I. G. E.; Schiesser, C. H. J. Org. Chem. 1990, 55,
1432–1438.
31. Lykakis, I. N.; Vougioukalakis, G. C.; Orfanopoulos, M. J. Org. Chem. 2006, 71,
8740–8747.
32. Van Sickle, D. E.; Mayo, F. R.; Arluck, R. M.; Syz, M. G. J. Am. Chem. Soc. 1967, 89,
967–977.
33. (a) Ziurys, L. M. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 12274–12279; (b)
Beuther, H.; Semenov, D.; Henning, Th.; Linz, H. Astrophys. J. 2008, 675(1,
Pt 2), L33–L36.
34. (a) Chastaing, D.; James, P. L.; Sims, I. R.; Smith, I. W. M. Faraday Discuss. 1998,
109, 165–181; (b) Stahl, F.; Schleyer, P. v. R.; Schaefer, H. F., III; Kaiser, R. I.
Planetary Space Sci. 2002, 50, 685–692; (c) Stahl, F.; Scheyer, P. v. R.; Bettinger,
H. F.; Kaiser, R. I.; Lee, Y. T.; Schaefer, H. F., III J. Chem. Phys. 2001, 114, 3476–
3487.
35. (a) Laufer, A. H.; Fahr, A. Chem. Rev. 2004, 104, 2813–2832; (b) Murphy, J. E.;
Vakhtin, A. B.; Leone, S. R. Icarus 2003, 163, 175–181; (c) Nguyen, H. M. T.;
Chandra, A. K.; Carl, S. A.; Nguyen, M. T. THEOCHEM 2005, 732, 219–224; (d)
Koshi, M.; Nishida, N.; Matsui, H. J. Phys. Chem. 1992, 96, 5875–5880; (e) Shin,
K. S.; Michael, J. V. J. Phys. Chem. 1991, 95, 5864–5869.
36. rCC, 1.208 Å, rCH, 1.062 Å, see: Szalay, P. G.; Thøgersen, L. S.; Olsen, J.; Kállay,
M.; Gauss, J. J. Phys. Chem. A 2004, 108, 3030–3034.