An efficient synthesis is described of hexabromides 5 and 6 by photobromination of biphenylene (1). Double dehydrobromination of hexabromides 5 and 6 with t-BuOK affords 5,6,8,10-tetrabromobenzocyclooctene (7) in nearly quantitative yield. The tetrabromide 7 is a valuable precursor for the preparation of functionalised substituted benzocyclooctenes (benzo[8]annulenes).
TutarA., CakmakO., and BalciM., Tetrahedron, 2001, 57, 9759.
20.
CakmakO., DemirtasI., and BalaydinH. T., Tetrahedron, 2002, 58, 5603.
21.
Crystallographic data for the structures 5 and 6 have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication numbers CCDC-151432 and 151433.
22.
(a) PaquetteL.A., “The Renaissance in Cyclooctatetraene Chemistry”, Tetrahedron, 1975, 31, 2855–2883.
23.
FrayG.I., and SaxtonR. G., “The Chemistry of Cyclooctatetrene and its Derivatives”, Cambridge University Press, Cambridge, 1978.
24.
ElixJ.A., SargentM. V., and SondheimerF., Chem. Commun., 1966, 508.
25.
MerkW., and PettitR., J. Am. Chem. Soc., 1967, 89, 4787.
26.
EmersonG.F., WattsL., and PettitR., J. Am. Chem. Soc., 1965, 87, 131.
27.
ElixJ.A., and SargentM. V., J. Am. Chem. Soc., 1969, 91, 4734.
BartonJ.W., LeeD. V., and ShepherdM. K., J. Chem. Soc. Perkin Trans. I, 1985, 1407.
33.
CelikI., TutarA., AkkurtM., OzcanY., and CakmakO., Acta Cryst. E, 2002, 58, 314.
34.
OthJ.F. M., MerenyiR., MartiniT., and SchröderG., Tetrahedron Lett., 1966, 3087; J.F.M. Oth, Pure Appl. Chem. 1971, 25, 582, J. Gasteiger, G.E. Gream, R. Huisgen, W.E. Konz and U. Schnegg, Chem. Ber. 1971, 104, 2412; G. Schröder, G. Kirsch, J.F.M. Oth, R. Huisgen, W.E. Konz and U. Schnegg, Chem. Ber. 1971, 104, 2405; L.A. Paquette and K.A. Henzel, J. Am. Chem. Soc. 1973, 95, 2726; J. Am. Chem. Soc., 1975, 97, 4649.
35.
FriedmanL., and LindowD. F., J. Am. Chem. Soc., 1968, 90, 2329; L. Friedman and A. H. Seitz, Org. Synth., 1964, 48, 12.
