Temperature Effect on [2 + 2] Intramolecular Photocycloadditions †
✍ Scribed by Becker, Dan; Cohen-Arazi, Yael
- Book ID
- 126250466
- Publisher
- American Chemical Society
- Year
- 1996
- Tongue
- English
- Weight
- 298 KB
- Volume
- 118
- Category
- Article
- ISSN
- 0002-7863
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📜 SIMILAR VOLUMES
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%.
There are two possible explanations for the high yields in the intramolecular [2 2] photocycloaddition of compounds 3a-d in which two styrene moieties are bridged by an oligooxyethylene linkage: one is the electronic effects of phenoxy oxygen atoms at the para-position of the vinyl group and the oth
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