title: Molecule-induced alkane homolysis with dioxiranes.
abstract: The mechanisms of C-H and C-C bond activations with dimethyldioxirane (DMD) were studied experimentally and computationally at the B3LYP/6-311+G**//B3LYP/6-31G* density functional theory level for the propellanes 3,6-dehydrohomoadamantane (2) and 1,3-dehydroadamantane (3). The sigma(C-C) activation of 3 with DMD (Delta G(*) = 23.9 kcal mol(-1) and Delta G(r) = -5.4 kcal mol(-1)) is the first example of a molecule-induced homolytic C-C bond cleavage. The C-H bond hydroxylation observed for 2 is highly exergonic (Delta G(r) = -74.4 kcal mol(-1)) and follows a concerted pathway (Delta G(*) = 34.8 kcal mol(-1)), in contrast to its endergonic molecule-induced homolysis (Delta G(*) = 28.8 kcal mol(-1) and Delta G(r) = +9.2 kcal mol(-1)). The reactivities of 2 and 3 with CrO(2)Cl(2), which follow a molecule-induced homolytic activation mechanism, parallel the DMD results only for highly reactive 3, but differ considerably for more stable propellanes such as 4-phenyl-3,6-dehydrohomoadamantane (1) and 2.
authors.affiliation: Department of Organic Chemistry, Kiev Polytechnic Institute, 37 Pobeda Avenue, 03056 Kiev, Ukraine.
authors.forename: A A
authors.initials: AA
authors.lastname: Fokin
authors.forename: B A
authors.initials: BA
authors.lastname: Tkachenko
authors.forename: O I
authors.initials: OI
authors.lastname: Korshunov
authors.forename: P A
authors.initials: PA
authors.lastname: Gunchenko
authors.forename: P R
authors.initials: PR
authors.lastname: Schreiner