Stereospecific double rearrangement of trans-3,4-dimethyl-cis,trans-cycloocta-1,5-diene to cis-3,4-dimethyl-cis,cis-cycloocta-1,5-diene

The chemistry of the highly strained cis,trans-cyclo-octa- 1,5-diene ring system* (1) is largely unexplored. there is a possibility that the corresponding 3,4-dimethyl derivatives 2 and 3 may be involved in the nonboat, “crossover” rearrangement of cis- 1,2-cis,trans- and cis- 1,2-cis,cis-dipropenylcyclobutanes (cCT and cCC, respectively),3 we have carried out a of the pyrolysis of trans-3,4-dimethyl-cis,trans- -octa- 1,5-diene (3). The present paper reports a thermal rearrangement of this compound.