102575-26-8Relevant articles and documents
Tricyclo2,8>oct-3-ene, -oct-4-ene, and -octane: Preparation and Thermolysis of the Hydro Derivatives of Octavalene
Christl, Manfred,Herzog, Clemens,Kemmer, Petra
, p. 3045 - 3058 (2007/10/02)
On treatment of 2,3,7,8-tetrabromobicyclooct-3-ene (7) with LiAlH4 an allylic rearrangement occurred with formation of tribromide 8, which was converted into 4-bromotricyclo2,8>oct-3-ene (9) by n-butyllithium.Sodium/tert-butyl alcohol and 9 reacted to give tricyclo2,8>oct-3-ene (4).Hydrogenation of 4 was achieved with diimine and afforded tricyclo2,8>octane (6) along with some bicyclooct-2-ene (10).Sodium iodide transformed 7 into the unrearranged iodide 12.Reduction of 7 with sodium in liquid ammonia led to bicycloocta-3,7-diene (11) in low yield.An allylic rearrangement took place when 7 was treated with AgNO3 to give nitrate 13.In another allylic rearrangement tribromide 14 was formed from 13 and LiAlH4.The reaction of 14 with n-butyllithium afforded 4-bromotricyclo2,8>oct-4-ene (15), and from 15 tricyclo2,8>oct-4-ene (5) was obtained by means of sodium/tert-butyl alcohol.By treatment of 4-bromooctavalene (16) with tert-butyllithium and subsequent hydrolysis, a new route to octavalene (1) was elaborated with virtually no formation of cyclooctatetraene as side product. - At 100 deg C 4 rearranged (t1/2 ca. 40 min) almost quantitatively to dihydrosemibullvalene (17).The decomposition of 5 at 200 deg C (t1/2 ca. 25 h) gave a complex mixture, in which only 11 has been identified.The saturated hydrocarbon 6 was converted virtually quantitatively into a 5.5 : 1 mixture of 3-methylenecycloheptene (18) and 1,3-cyclooctadiene (19) at 160 deg C (t1/2 ca. 8 h).Possible mechanisms of these rearrangements are discussed.
