102115-82-2Relevant articles and documents
Spiroalkyl and Spiroalkylmethyl Radicals
Roberts, Charles,Walton, John C.,Maillard, Bernard
, p. 305 - 312 (2007/10/02)
Spiroheptan-3-yl radicals were generated by bromine abstraction from 3-bromospiroheptane and observed by e.s.r. spectroscopy.Both spiroheptane-3-yl and spiroheptan-2-yl radicals were observed on hydrogen abstraction from from spiroheptane.The measured proportions of the two radicals indicated that hydrogen abstraction occurs at roughly the same rate from both C(2) and C(3).The e.s.r. parameters of both radicals show that they are structurally very similar to cyclobutyl radicals.The spiroheptan-2-yl radical rearranges to the cyclobutenylpropyl radical at temperature above ca. 290 K.The photochemical reactions of spiroheptane with bromotrichloromethane and bromine were investigated.Spiroheptylmethyl radicals were generated from the corresponding bromo compound; their rearrangement to 1-allylcyclobutylmethyl radicals was monitored by e.s.r. spectroscopy.Indirect evidence suggested a further rearrangement of 1-allylcyclobutylmethyl radicals to 4-methylenehept-6-enyl radicals.From the activation energy for β-scission in spiroheptylmethyl radicals it was possible to show that the ring strain in spiroheptane cannot exceed twice the ring strain in cyclobutane by more than ca. 3 kcal mol-1.
