- 作者: 廖俊臣 ; 許宗雄 ; 林和盛
- 作者服務機構: 清華大學化學系
- 中文摘要: The title epoxydiketones were prepared stereoselectively; direct epoxidation of 3a-c with MCPBA produced syn isomers 1a-c whereas epoxidation of 4a-d followed by saponification of the spirolactone rings gave anti isomers 2a-c. The stereochemistry of 1a and 2a was established by X-ray diffraction, whereas that of the remaining epoxydiketones was determinded from the correlation of visible, /sup 1/H, and /sup 13/C NMR spectral data; the differences between spectra of the corresponding syn and anti isomers are explained in terms of through-space interaction and steric effects. Photolysis of syn isomers 1a-c afforded the corresponding naphthalenes in almost quantitative yields; in contrast, irradiation of anti isomers 2a-c gave complicated mixtures. The quantum yield of disappearance of 1a was 52 times that of 2a. Reaction mechanisms are proposed to account for the product formation. The differences in the photochemical behavior of the title syn and anti isomers are rationalized in terms of stereoelectronic effects of the epoxy rings in the syn isomers.
- 英文摘要: --
- 中文關鍵字: Epoxydiketone; Synthesis; X-Ray Diffraction; Stereochemistry; Molecular Orbital Calculation; Photochemistry
- 英文關鍵字: 合成;X-射線繞射;立體化學;分子軌域計算;光化學