Bicyclo decatetraenes

Phenyltrichloromethylmercury has been found to be an ineffective carbene source for the cyclopropanation of a number of (CH)jo alkenes (snoutene, basketene, bullvalene, etc.) whereas the Makosza procedure works well. With the bicyclo-decatetraene (74) only the bis-adduct (76) was obtained (Scheme 11), and this contrasts sharply with the 1974 report of Schroder, where (75 X = Br) was obtained. However, the intervention of (75 X == Cl) is reasonably implicated in the formation of (76). 

The prediction on the basis of orbital symmetry analysis that cyclization of eight-n-electron systems will be connotatoiy has been confirmed by study of isomeric 2,4,6,8-decatetraenes. Electrocyclic reaction occurs near room temperature and establishes an equilibrium that favors the cyclooctatriene product. At slightly more elevated temperatures, the hexatriene system undergoes a subsequent disrotatory cyclization, establishing equilibrium with the corresponding bicyclo[4.2.0]octa-2,4-diene ... 

Envahnt verden soli an diescr Stelle auch der Befund, daB die Isomerisierung des Bullvalens (III) in Bicyclo [4.2.2]decatetraen-(2,4,7,9) (II) (S. 436) auch durch Quecksilberbromid nioglich ist3,... 

Tricyclo[3.3.2.(H>< ]deca-2,7,9-trienes from bicyclo[4.2.2]decatetraenes... 

Decatetraene gives 7,8-dimethylene-cA-bicyclo[4.2.0]octane and 3,4-dimethylenecyclooctene in a 1 3 ratio, respectively, at temperatures well above 300°C in a flow system (Scheme 11.88). ... 

Bicyclo[6,2,0]decatetraenes afford the corresponding dianion (869) on treatment with potassium amide in liquid ammonia. ... 

PROBLEM 13.14 The all -cis cyclodecapentaene forms a new, cross-ring bond (see below). As the molecule warms up, a bicyclo[4.4.0]decatetraene is formed. Write... 

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