Abstract: Thermal rearrangement of cis-l-vinylcyclonon-3-en-1-ol (l-OH) or of the corresponding trimethylsiloxy compound, 1-OTMS, followed by hydrolysis yields mainly cis-5- cycloundecenone (5) which represents a [1, 3] sigmatropic shift resulting in a two-carbon ring expansion. The minor products result from loss of the cis stereochemistry, a [3, 3] sigmatropic shift, and, for the alcohol, &hydroxy olefin cleavage and elimination. The loss ...
