278-07-9Relevant academic research and scientific papers
1,4-CYCLOHEPTYLENE AND THE RELATED ALLYLIC DIRADICALS. THERMAL NITROGEN EXTRUSION FROM 6,7-DIAZABICYCLONON-6-ENES
Uyehara, Tadao,Takahashi, Masayuki,Kato, Tadahiro
, p. 1241 - 1244 (2007/10/02)
Thermal nitrogen extrusion of 2-methylene-6,7-diazabicyclonon-6-enes and 6,7-diazabicyclonona-2,6-dienes proceeded easily to give closure and cleavage products via the corresponding 5-methylene-1,4-cycloheptylenes and 4-cyclohepten-1,3-ylenes, respectively.
The Kinetics and Mechanism of Ring Opening of Radicals containing the Cyclobutylcarbinyl System
Beckwith, Athelstan L. J.,Moad, Graeme
, p. 1083 - 1092 (2007/10/02)
The kinetic parameters of β-fission of radicals containing the cyclobutylcarbinyl system have been determined by analysis of the mixtures obtained when suitable chloro-compounds are treated with tributylstannane.Under these conditions ring opening is irreversible and in the rigid bicyclic system (4) is under stereoelectronic control.For ring opening of cyclobutylcarbinyl radical (8) kf = 4.3 x 103 s-1 at 60 deg C, and the best values of the activation parameters appear to be ΔH(excit.) = 12.2 kcal mol-1 and ΔS(excit.) = -7.4 cal mol-1 K-1.Monocyclic systems undergo preferential fission of the more substituted βγ-bond.Methyl substituents at the α-, β-, or δ-positions have little effect but γ-substitution strongly enhances the rate of ring opening.The transition state is reactant-like and has a similar disposition of centres to that (1) for homolytic addition.
