Dienophilic and dipolar additions to bicyclo[2.1.0]pent-2-ene
作者:Waldemar Adam、Axel Beinhauer、Ottorino De Lucchi、Robert J. Rosenthal
DOI:10.1016/s0040-4039(00)94185-6
日期:1983.1
dienophiles triazolinedione, singlet oxygen and in part tetracyanoethylene cyclo-add to bicyclo[2.1.0]pent-2-ene (1) across the central σ-bond to give bicyclo[2.2.1]heptene-type adducts, while the dipoles phenyl azide, benzonitrile oxide and diphenyldiazomethane cyclo-add at the π-bond with expected stereochemistry.
Ring-Opening Metathesis Polymer Sphere-Supported <i>s</i><i>eco</i>-Porphyrazines: Efficient and Recyclable Photooxygenation Catalysts
作者:Matthew J. Fuchter、Brian M. Hoffman、Anthony G. M. Barrett
DOI:10.1021/jo052156t
日期:2006.1.1
subsequently converted into its zinc seco-derivative. Polymerization gave the corresponding ROMPgel and ROMPsphere (ROMP = ring-opening metathesis polymer) reagents, the latter of which proved efficient as an immobilized catalyst for the sensitized production of singlet oxygen for the purification-minimized parallelsynthesis of endoperoxides and ene adducts.
γ-heterosubstituted γ-methyl-α,β-butenolides are presented, starting mainly from C3 synthons (glyceraldehyde, glycidaldehyde, acrolein and 2,3-epoxypropyl ethers). Good general methods for the preparation of γ-hydroxymethyl-α,β-butenolide 2, several of its ether derivatives, as well as of γ-bromomethyl-α,β-butenolide 5, are given. The reactivities of these structurallysimple but highly functionalized compounds
High Reactivity of Heterocoerdianthrones (HCDs) in Photoperoxidation and Thermal Stability of Their Endoperoxides. Use of HCD as a Photosensitizer under Sunlight
The measured reactivity indices (β-values) of heterocoerdianthrones (HCDs) in self-sensitized photoperoxidation indicate a high reactivity toward singlet-oxygen. Such a high reactivity is not only due to an effective singlet-oxygen production due to the highly fluorescent character, but also due to a strained structure, as predicted by a molecular calculation. On the other hand, the large thermal stability of their endoperoxides (POs), revealed by the large activation energy in thermal decomposition, is also explained by considering the strained structure of the parent HCDs. As a prospect of solar synthesis, one of the HCD derivatives was applied to a photosensitizer for singlet-oxygen oxidation.