Trans-bicyclo deca-2,4-diene

The bridgehead diolefins 210 and 211, which, like 55, are formally alkylene-bridged derivatives of trans, frans-cycloalkenes, have been reported (165) (Scheme 10). The stability of 211 toward heat, air, and moisture is in contrast to that of the unsubstituted bicyclo[4.2.2]deca-1,5-diene (210). The latter diene was obtained by a kinetically controlled reductive deiodination of 209, which leads to the cleavage of the cyclobutano bridge in preference to the ethano bridge, despite the greater thermodynamic stability of the monocyclic diene to be expected from the latter reaction. 

The trons-cycloalkenes 37a, 67, and trans-cyclononene 227 react with diironnonacarbonyl 228 to form the tetracarbonyliron(O) complexes 229-231 with the frans-cyclooctene complex 229 being significantly more stable than that of trons-cyclodecene 231 (177). The bicyclic triene 232 reacts with 228 preferentially at one of the trans double bonds of the trans, trans- cy-clodecadiene substructure. In line with the expected stability, the trans, cis-cycloocta-1,5-diene 234 and trans, ris-cycloocta-1,3-diene 236 react with 228 exclusively at the trans double bond to give the complexes 235 and 237. In the complex 238, tetracarbonyliron(O) is bonded to the bridgehead double bond of bicyclo[4.3.2]deca-7,9-diene (184b) (177). 

The kinetics gave log k = 9.53 — 31 200/23RT. Further both cis- and trans-l,S-dimethylenebicyclo[4.2.0]octane were prepared and found to be stable under the reaction conditions, although at higher temperatures, the triene was formed presumably via bicyclo[6.2.0]deca-l,7-diene (Scheme 11.89). 

Nine- and Ten-membered Rings.—Reduction of 1-bromo-cw-cyclononene and either l-bromo-trans,ds- or l-bromo-ds,cis-cyclonona-l,5-diene with sodium in liquid ammonia gave ds-cyclononene and cis,ds-cyclonona-1,5-diene, respectively." Thermolysis of bicyclo[7,l,0]deca-l,7-diene and bicyclo[8,l,0]undeca-1,8-diene gives 3-methylene-cis,ds-cyclonona-l,4-diene and a mixture of 3-methylene-ds,ds-cyclo-deca-1,4-diene and 10-methylenebicyclo[5,3,0]dec-8-ene, respectively. Cyclo-nonanone tosylhydrazone gives ds-cyclononene exclusively when treated with methyl or n-butyl lithium, whereas both cis- and trans-cyclodecenes are obtained from cyclo-decanone tosylhydrazone. The cis.trans olefin ratio in this case is solvent dependent probably, because of the effect of solvent on the tosylhydrazone conformation." ... 

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