Photoinitiated Domino Reactions: N-(Adamantyl)phthalimides and N-(Adamantylalkyl)phthalimides
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- 作者：Margareta Horvat ; Helmut Grner ; Klaus-Dieter Warzecha ; Jrg Neudrfl ; Axel G. Griesbeck ; Kata Mlinari-Majerski ; Nikola Basari
- 刊名：Journal of Organic Chemistry
- 出版年：2009
- 出版时间：November 6, 2009
- 年：2009
- 卷：74
- 期：21
- 页码：8219-8231
- 全文大小：1166K
- 年卷期：v.74,no.21(November 6, 2009)
- ISSN：1520-6904
文摘
Phthalimides 1−6 undergo photochemical reactions upon direct irradiation as well as triplet sensitization and give rise to new products. Besides formation of the primary photoproducts, the first photochemical step initiates a subsequent thermal domino reaction or a domino sequence of a thermal and a photochemical reaction. The latter, involving two photochemical intramolecular γ-H abstractions, was observed with phthalimides 1, 3, and 6 and delivered stereospecifically the hexacyclic benzazepine products 12, 19, and 27, respectively. The lowest triplet states of 1−6 were characterized in several solvents upon direct and acetone-sensitized excitation. The intermolecular electron transfer from triethylamine and DABCO was studied, and the radical anions were observed. Electrochemical measurements showed that intramolecular electron transfer from the adamantyl group of 1−6 to the lowest triplet state of the phthalimides is not feasible. The formation of products can be explained by intramolecular H-abstraction from the (alkyl)adamantane to the excited phthalimide, either from the excited singlet state or a hidden upper excited triplet state.