4663-23-4Relevant academic research and scientific papers
Homolytic Rearrangements of Bicyclohexane and Bicycloheptane
Walton, John C.
, p. 1371 - 1376 (2007/10/02)
Free radicals abstract hydrogen from both the bridge and bridgehead sites in bicyclohexane (4).The bicyclohexan-1-yl radical was observed by e.p.r. spectroscopy.The bicyclohexan-2-yl radical rearranges by stereoelectronically forbidden β-scission to give cyclohex-3-enyl radicals.Unlike other cyclobutanes, compound (4) undergoes an SH2 reaction with bromine atoms.Free radicals abstract hydrogen only from the methylene groups of the C5 ring in bicycloheptane (15a).The bicycloheptan-2-yl radicals were observed by e.p.r. spectroscopy, as was their rearrangement, by stereoelectronically allowed β-scission, to 2-(cyclopent-2-enyl)ethyl radicals.Bromine atoms abstract hydrogen from (15a) and no SH2 reaction was detected.The radicals and their rearrangements were studied by semi-empirical MINDO/3 and MNDO methods.
Thermal Unimolecular Decomposition of Bicyclopropyl and Deuterated Analogues: Infrared Photoactivation as a Diagnostic Tool in Mechanistic Organic Chemistry
Farneth, William E.,Thomsen, Marcus W.
, p. 4851 - 4855 (2007/10/02)
The infrared photochemistry of bicyclopropyl yields product mixtures that are not easily rationalized on the basis of the mechanistic scheme suggested by previous pyrolysis work.As a result of this inconsistency the thermal chemistry of bicyclopropyl and analogues deuterated specifically on one ring has been reexamined.A significant new reaction channel involving the chemically activated decomposition of cyclohexene to ethylene and butadiene has been demonstrated.Evidence for the involvement of chemically activated cyclohexene is as follows: (1) isotopic labelingstudies implying a symmetric intermediate, (2) a pressure-dependent ratio of cyclohexene to butadiene and ethylene, (3) good agreement between experimental and calculated values for the unimolecular rate constant for retro-Diels-Alder decay of hot cyclohexene.A comprehensive mechanism for the unimolecular decay of bicyclopropyl is proposed.The important elements of this mechanism are a single first-formed 1,3 biradical common to all products and the intervention of chemical activation in the generation of several of the secondary products.
