About the stereochemistry of intramolecular [2+2] photocycloadditions
โ Scribed by D Becker; N Haddad
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- French
- Weight
- 203 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
โฆ Synopsis
The stereoselectivity in [2+2] photocycloaddition was studied on System I. Compounds 2, m, and 15a cyclize in high yield and the selectivity is higher than 94%.
๐ SIMILAR VOLUMES
Lewis acid catalyzed condensation of unsaturated orthofonnates with dienol ethers gives enone-acetals suitable for intramolecular photocycloadditions, yielding heterocyclic precursors to sesquiterpene lactones.
It was found that in [2+2] intramolecular photocycloaddition the isomer ratio in system II is different from system I. Compounds 1 and 20 cyclize with high stereoselectivity to give in high yield 3 and 21 respectiveIy. The mechanistic consequences are discussed. The mechanism of [2+2] photocycloaddi
## Abstract The photochemical reactions of indaneโ1โthiones 4 were examined. Irradiation of indaneโ1โthiones 4cโd bearing ฮดโhydrogen atoms in the side chain gave cyclic thiol derivatives 5cโd via ฮดโhydrogen atom abstraction by the excited thiocarbonyl sulfur. Irradiation of 2โallylindaneโ1โthiones
Intramolecular [3+2] -photocyctoadditions of alkenyl methyl 1,4-naphthalenedicarboxylates, which contain rather remote alkene moieties corresponding to isobutene or a-methylstyrene, proceeded largely depending on the chain lengths to give [3+2]-adducts having nine-to eleven-membered ring systems as