38511-90-9Relevant academic research and scientific papers
Rearrangements of 1-Cyclohexenylmethylenes and Their Relevance to the Mechanism of the Phenylcarbene Rearrangement
Miller, Paula C.,Gaspar, Peter P.
, p. 5101 - 5107 (2007/10/02)
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.
Organic Photochemistry with 6.7-eV Photons. The Divergent Photobehavior of exo- and endo-7-Methyl-2-norcarene
Leigh, William J.,Srinivasan, R.
, p. 3970 - 3979 (2007/10/02)
The photochemistry of exo- and endo-7-methylbicyclohept-2-ene (7-methyl-2-norcarene) upon direct and toluene-sensitized photolysis has been investigated.Direct photolysis of the two isomers in hydrocarbon solution with monochromatic 214-nm light leads to widely divergent photobehavior.Ring opening, yielding cis-5-methyl-1,3,6-heptatriene (via a formal process), and exo-endo isomerization are major decomposition pathways in both cases, accounting for 30-45percent of the observed products.The formation of 7-methylnorbornene and 4-methylbicyclohept-2-ene is observed to proceed stereospecifically in each case, while the formation of cyclopropyl ring opening/hydrogen migration products appears to depend strongly on the orientation of the methyl group in the starting isomer.Common biradical intermediates are thus believed not to be involved in the direct photolyses of 2 and 3.Toluene-sensitized photolysis of the two isomers leads to formation of exo-4-methylbicyclohept-2-ene (the photochemical vinylcyclopropane rearrangement) and exo-endo isomerization.These results are rationalized in terms of the expected behavior of two common biradical intermediates, which are formed with different efficiencies from the isomeric 2 and 3 upon triplet sensitization.
