110255-11-3Relevant academic research and scientific papers
Hydrogen Abstraction from Spiroalkanes
Roberts, Charles,Walton, John C.
, p. 841 - 846 (2007/10/02)
Hydrogen abstraction from spirohexane by t-butoxyl radicals gave spirohex-2-yl radicals; their rearrangement to cyclobutenylethyl radicals was followed by kinetic e.s.r. spectroscopy.Hydrogen abstraction at the methylene groups adjacent to the cyclopropyl rings in higher spiroalkanes gave spiroalk-2-yl radicals, which rearranged to cycloalkenylethyl radicals too rapidly for detection, together with secondary radicals from abstraction at the other methylene groups in the larger ring.From the measured concentrations of the cycloalkenylethyl and secondary radicals the rate of hydrogen abstraction at the cpm sites relative to the rate of hydrogen abstraction at the secondary sites was determined; significant activation of the cpm hydrogens was found.This activation was attributed to a pseudo-allyl type of effect, i.e., to delocalisation of the unpaired electron into the Walsh orbitals of the cyclopropane ring of the spiroalk-2-yl radicals; semi-empirical SCF-MO calculations supported this explanation.Photobromination of spirohexane occured mainly by SH2 attack of bromine atoms at the cyclopropane methylene carbons with fission of either C-C bond.
