35776-64-8Relevant academic research and scientific papers
Unusual facial selectivity in the cycloaddition of singlet oxygen to a simple cyclic diene
Davis, Kelly M.,Carpenter, Barry K.
, p. 4617 - 4622 (2007/10/03)
Syntheses of 5-isopropyl-1,3-cyclohexadiene and syn-5-isopropyl-2,3-dioxabicyclo[2.2.2]octane, by routes that would allow completely diastereoselective introduction of deuterium labels, are described. The reaction of the isopropyl cyclohexadiene with singlet oxygen is shown to give an endoperoxide that is derived by preferential attack on the more sterically hindered face of the diene. A possible mechanistic explanation of this result is that the attack from the less hindered face leads to "ene" reaction rather than endoperoxide formation. However, this mechanism would require that the "ene" reaction and cycloaddition proceed via a common intermediate-presumably a perepoxide.
Primary Deuterium Kinetic Isotope Effects for the Thermal Sigmatropic Rearrangement of 7-Methylocta-1,3(Z),5(Z)-triene
Baldwin, John E.,Prakash Reddy, V.
, p. 8223 - 8228 (2007/10/02)
7-Methylocta-1,3(Z),5(Z)-triene isomerizes to 2-methylocta-2,4(Z),6(Z)-triene over the temperature range 60-115 deg C through a first order process characterized kinetically by the activation parameters log AH = 9.8 and EaH = 21.5 kcal/mol.Parallel kinetic work with the 7-deuterio-7-methyloctatriene establishes the Arrhenius parameters log AD = 10.3 and EaD = 23.5 kcal/mol.Thus AD/AH = 3.2 and (EaD-EaH) = 2.0 kcal/mol, and a substantial tunneling component for the sigmatropic hydrogen migration is evident.
