Interactions of singlet oxygen with 2,5-dimethyl-2,4-hexadiene in polar ano non-polar solvents evidence for a vinylog ene-reaction
作者:Klaus Gollnick、Axel Griesbeck
DOI:10.1016/0040-4020(84)85006-1
日期:1984.1
a substituted 1,3-diene. - Kinetic analysis shows that “physical” quenching, endoperoxide and vinylog ene-product formations proceed with solvent-inde pendent rates; the rates of dioxetane and ene-product formations, however, are solvent-dependent. - A mechanism (Scheme 3) is proposed, according to which endoperoxideformation is due to a concerted singlet oxygen reaction with the s-cis-conformational
Regio-controlled functionalization of 2,5-dimethyl-2,4-hexadiene into epoxy alcohols by photooxygenation in the presence of titanium(IV) or vanadium(V)
作者:Waldemar Adam*、Eugen Staab
DOI:10.1016/s0040-4039(00)80141-0
日期:——
Using Ti(OiPr)4 as oxygen transfer catalyst, the diene 1 affordedexclusively the epoxyalcohol 1c, but VO(acac)2 gave exclusively the isomerized epoxyalcohol 2c during its ene reaction with singlet oxygen.
Sensitized photo-oxygenation of a wide variety of acyclic 1,3-dienes was investigated. The 1,4-cycloaddition of singlet oxygen to acyclic conjugated dienes was closely related to the thermal Diels-Alder reaction in stereospecificity, and steric and electronic effects of substituents. Reactivity order of singlet oxygen toward conjugated dienes and isolated C—C double bonds was exhibited as follows: