Oxidative Cleavage of the Zero-Ene-Bridge in Bicycles

For similar reactions, see ref. [85] [86]. The ratio of the components in the equilibrium VIII/143 VIII/144 depends very much on the number of substituents. The percentage of the bicycle is increased with substitution (e.g. no substituents, 10.8% bicycle 7,7-dimethoxy, 95%) [87], 

Oxidative Cleavage of the Zero-Ene-Bridge in Bicycles 

Ring Expansion by Cleavage of the Zero Bridge in Bicycles 

The incorporation of a cu-functionalized side chain in the a-position of ethyl 2-oxocyclooctane-l-carboxylate (VIII/164) yielded VIII/165, which by loss of water (distillation in vacuo) gave 9-oxabicyclo[6.5.0]tridec-l(8)-ene (VIII/166). Oxidation of VIII/166 with an excess of mcta-chloroperoxybenzoic acid for a short period of time (to avoid Baeyer-Villiger oxidation of the product oxolac-tone to dilactones9)) gave a 46 % yield (from VIII/164 of VIII/167) [98]. 

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VIII. 4. Oxidative Cleavage of the Zero-Ene-Bridge in Bicycles... 

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