19036-81-8Relevant articles and documents
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Roffia et al.
, p. 405 (1973)
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Kinetics of thermal gas-phase isomerizations and fragmentations of cis- and trans-1-(E)-propenyl-2-methylcyclobutanes at 275°C
Baldwin, John E.,Burrell, Richard C.
, p. 3249 - 3256 (2007/10/03)
Kinetic studies of the thermal isomerization and fragmentation reactions exhibited by cis- and trans-1-(E)-propenyl-2-methylcyclobutanes at 275°C in the gas phase have provided first-order rate constants for cis,trans interconversions of the cyclobutanes, 1,3-carbon migrations leading to 3,4- and 3,6-dimethylcyclohexenes, isomerizations providing directly and indirectly four acyclic dienes, and fragmentations to ethylene, propene, and mixtures of pentadienes and hexadienes. Both cis and trans isomers of 1-(E)-propenyl-2-methylcyclobutane form trans-3,4-dimethylcyclohexene faster than they are converted to cis-3,4-dimethylcyclohexene; the trans reactant gives rise to cis-3,6-dimethylcyclohexene in preference to its trans isomer, while the cis starting material gives neither at measurable rates; both form the relatively minor product 1,6-(Z)-octadiene. The rate constants derived from 35 kinetic runs starting with four distinct 1-(E)-propenyl-2-methylcyclobutane samples are consistent to within narrow error limits. The stereomutations, isomerizations, and fragmentations of the 1-(E)-propenyl-2-methylcyclobutanes are interpreted in terms of competitive processes involving conformationally flexible short-lived 2-(E)-octene-4,7-diyl and 3-methyl-5-(E)-heptene-1,4-diyl diradicals.
