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Title: Exploratory Studies of H-Atom Abstraction and Silyl-Transfer Photoreactions of Silylalkyl-Ketones and (Silylalkyl)Phthalimides
Authors: Lee, Yean-Jang;Ling, R.;Mariano, P. S.;Yoon, U. C.;Kim, D. U.
Contributors: 化學系
Date: 1996-05
Issue Date: 2012-12-10T02:51:23Z
Publisher: American Chemical Society
Abstract: Exploratory studies have been conducted to probe competitive H-atom abstraction and SET-promoted, silyl-transfer reactions of excited states of silylalkyl ketones and (silylalkyl)phthalimides. Photochemical investigations with the (silylalkyl)phthalimides have demonstrated that typical γ-H atom abstraction reactions occur upon irradiation in less polar and less silophilic solvents. In contrast, irradiation of these substances in polar−protic−silophilic solvents results in product formation via pathways involving SET-induced desilylation. Photoreactions of silylamido−aryl ketones in either nonsilophilic or silophilic solvents take place almost exclusively by sequential SET silyl-transfer routes to produce azetidine products. Finally, the chemical selectivities of photochemical reactions of silylpropyl−aryl ketones appear to depend on medium polarity and silophilicity. Irradiation of these substrates in less polar−nonsilophilic solvents leads to almost exclusive formation of acetophenone and vinyltrimethylsilane in essentially equal yields by a reaction pathway initiated by γ-H atom abstraction and 1,4-biradical fragmentation. However, irradiation of these substances in polar−silophilic solvents produces acetophenone and vinyltrimethylsilane in an ca. 1.7:1 ratio reflecting the fact that a silyl-transfer pathway competes with H-atom abstraction under these conditions.
Relation: J. Org. Chem., 61(10): 3304-3314
Appears in Collections:[Department of Chemistry] Periodical Articles

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