Model studies of beta-scission ring-opening reactions of cyclohexyloxy radicals: application to thermal rearrangements of dispiro-1,2,4-trioxanes.
A DFT study of model cyclohexyloxy radicals (8a-c, 9) show that (a) the presence of an adjacent oxygen atom, and (b) alpha-substituents on the cyclohexyl ring, particularly methoxy, accelerate the rate of beta-scission ring-opening reactions. Consistent with theoretical results, thermolysis of the methoxy-substituted dispiro-1,2,4-trioxane 10 afforded the structurally novel, 14-membered macrocyclic keto lactone 11 as the major isolable product.
Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
Stefan
S
Erhardt
Stuart A
SA
Macgregor
Kevin J
KJ
McCullough
Karen
K
Savill
Benjamin J
BJ
Taylor
D003500:Cyclization; D003510:Cyclohexanes / Q000737:chemistry*; D005609:Free Radicals; D008958:Models, Molecular; D013816:Thermodynamics
D003510:Cyclohexanes; D005609:Free Radicals