Rearrangements of 1-Cyclohexenylmethylenes and Their Relevance to the Mechanism of the Phenylcarbene Rearrangement

Article abstract of DOI:10.1021/jo00017a021

Gas-phase pyrolysis of 1-cyclohexenyldiazomethane (17) and (2-methyl-1-cyclohexenyl)diazomethane (36) leads to the generation of cyclohexenylmethylenes, 13 and 27, respectively, whose intramolecular rearrangement mechanism can be inferred from the stable end products.These substituted vinylmethylenes undergo intramolecular ?-addition, but apparently do not participate in all-carbon Wolff rearrangement.The relevance of these results to the mechanism of the phenylcarbene rearrangement is discussed, and it is suggested that a ?-route with a bicycloheptatriene-like transition state may operate.An attempt to generate 1,3-cyclohexadienylmethylene is described.