1772
S. Majumder, A. L. Odom / Tetrahedron Letters 49 (2008) 1771–1772
[Li(TMEDA)]2C8H8 (3) was prepared according to the
known literature procedure.5 To the in situ generated lith-
ium COT (3) cooled with an ice bath was added 1,2-dibro-
moethane. Further stirring at room temperature produced a
yellow mixture, which upon acidic work-up followed by dis-
tillation produced COT (1) in 62% isolated yield.
Acknowledgements
The authors wish to thank the National Science Foun-
dation and Petroleum Research Fund administered by
the American Chemical Society for funding.
References and notes
2. Experimental
1. (a) Fray, G. I.; Saxton, R. G. The Chemistry of Cyclooctatetraene and
its Derivatives; Cambridge University: Cambridge, 1978; (b) Paquette,
L. A. Acc. Chem. Res. 1993, 26, 57; (c) Huisgen, R.; Mietzsch, F.
Angew. Chem. 1964, 76, 36; Angew. Chem., Int. Ed. Engl. 1964, 3, 83;
(d) Spitler, E. L.; Johnson, C. A., II; Haley, M. M. Chem. Rev. 2006,
106, 5344. For a review on the synthesis of substituted derivatives
see:(e) Wang, C.; Xi, Z. Chem. Commun. 2007, 5119.
2. (a) Comprehensive Organometallic Chemistry, 2nd ed.; Abel, E. W.,
Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford, 1996; Vol. 4,
(b) Edelmann, F. T. New J. Chem. 1995, 19, 535; (c) Avdeef, A.;
Raymond, K. N.; Hodgson, K. O.; Zalkin, A. Inorg. Chem. 1972, 11,
1083. For some recent examples see: (d) Dunn, S. C.; Nazari, N.;
Cowley, A. R.; Green, J. C.; Mountford, P. Organometallics 2006, 25,
1755; (e) Dunn, S. C.; Hazari, N.; Jones, N. M.; Moody, A. G.; Blake,
A. J.; Cowley, A. R.; Green, J. C.; Mountford, P. Chem. Eur. J. 2005,
11, 2111; (f) Hill, A. F.; Smith, M. K. Organometallics 2007, 26,
3900.
3. Willsta¨tter, R.; Waser, E. Chem. Ber. 1911, 44, 3423.
4. Reppe, W.; Schlichting, O.; Klager, K.; Toepel, T. Justus Liebigs Ann.
Chem. 1948, 560, 1.
5. (a) Gausing, W.; Wilke, G. Angew. Chem., Int. Ed. Engl. 1978, 17,
371. For a study on the nature and mechanism of formation for 3 see:
(b) Hoye, T. R.; Kabrhel, J. E.; Hoye, R. C. Org. Lett. 2005, 7,
275.
Under nitrogen atmosphere a 2 L 2-neck round bottom
flask was charged with n-BuLi (750 mL, 1.6 M solution in
hexane, 1200 mmol) and 1,5-cyclooctadiene (2) (49 mL,
400 mmol) in 150 mL dry pentane. The mixture was cooled
to 0 °C and TMEDA (182 mL, 1200 mmol) was added via
syringe. The resulting solution was stirred at room temper-
ature for 2 d. The solution turned red after an hour, and
orange crystals had formed after a day. Then, the mixture
was again cooled to 0 °C and 1,2-dibromoethane (82.7 g,
440 mmol) was added slowly over 30 min. The 1,2-dibro-
moethane reaction is quite exothermic and should be done
slowly with care. The mixture was stirred overnight at
room temperature. The solution was diluted with 300 mL
of pentane, and the organic layer was washed with 5%
acetic acid (250 mL ꢁ 2) followed by saturated NaHCO3
(250 mL ꢁ 2). The organic layer was dried with Na2SO4,
and the solvent was removed under rotary evaporation.
The crude yield is quite high (80–90%) with the major
impurity being a small amount of cyclooctadiene (2). The
crude product was purified by distillation using a Vigreux
column under nitrogen to yield 26.8 g (62%) of cycloocta-
6. Wetzel, T. G.; Dehnen, S.; Roesky, P. W. Organometallics 1999, 18,
3835.
7. Simons, L. H.; Lagowski, J. J. Tetrahedron Lett. 2002, 43, 1771.
8. Gottfriedsen, J.; Miloslavina, A.; Edelmann, F. T. Tetrahedron Lett.
2004, 45, 3583.
1
tetraene (1). H NMR (CDCl3, 500 MHz): d 5.77 (8H, s);
13C NMR (CDCl3, 125 MHz): d 132.10. MS: 104 (M+).