Ring-Cleavage Reactions of Small-Ring Compounds by Photo- Induced Electron Transfer

通过光诱导电子转移进行小环化合物的开环反应

• 批准号: 62550616
• 负责人: SHIMA Kensuke
• 金额: $ 0.38万
• 依托单位: Miyazaki University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62550616/
• 关键词: Oxetanes; Cyclobutanes; Thietane; Photosensitized Reaction; X-ray Crystallographic Analysis; Through-Bond相互作用; π-σ相互作用; 小員環化合物; Trough-Bond相互作用

(1) photosensitized Ring-Cleavage Reaction of 2,2-Diaryloxetanes by Aromatic Nitriles. Photosensitized reactions of 2,2-diaryloxetanes by electron acceptors, which give such ring-cleavage products as substituted benzophenones and alkenes, have been investigated. Quantum yields for the ring cleavage vary with substituents on both the aryl group and oxetane ring. The quantum yield increases with increase in electron-donating ability of the oxetane. The limiting quantum yields in the case of 1,4-dicyanonaphthalene-photosensitized reaction of 2,2-di-p-tolyl- or 2,2-bis(p-methoxyphenyl)-3,3,4-trimethyloxetane exceed unity.(2) Photochemical Reactions of 2,2-Diaryloxetanes in the Presence of Electron Donor. Photochemical ring-cleavage reactions of 2,2-diaryloxetanes in the presence of triethyl-amine occurred to give 1,1-diarylethene selectively.(3) Ring-Cleavage Reactions of 1,2-Diarylcyclobutanes. We found that aryl-substituted cyclobutanes reveal remarkable structure dependences in photochemical and thermal ring-splitting reactions. The reactivities of cyclobutanes are explic-itly classified into two groups of "reactive" and "unreactive" cyclobutances. Therefore, molecular structures of diarylcyclobutanes have been determined by single-crystal X-ray analyses. Although the distances and angles of cyclobutane rings are relatively normal, the torsional angles between the aryl ring and the plane involving the ipso carbon and the aryl-substituted carbons of cyclobutane ring are close to 90゜ in the cases of "reactive" cyclobutanes but vary small in the cases of "unreactive" cyclobutanes.

(1)芳香腈光敏2,2-二乙基氧乙烷的环裂解反应。研究了2,2-二芳基氧乙烷与电子受体的光敏反应，得到了取代二苯甲酮和烯烃等环裂解产物。环裂解的量子产率随芳基和氧烷环上取代基的不同而变化。量子产率随氧烷给电子能力的增加而增加。2,2-二对甲苯-或2,2-二（对甲氧基苯基）-3,3,4-三甲基氧乙烷的1,4-二氰萘光敏反应的极限量子产率超过1。(2)电子给体存在下2,2-二乙基氧乙烷的光化学反应。2,2-二乙基氧烷在三乙胺存在下发生光化学裂解反应，选择性地得到1,1-二乙基乙烯。(3) 1,2-二芳基环丁烷的环裂解反应。我们发现芳基取代环丁烷在光化学和热分裂环反应中表现出明显的结构依赖性。环丁烷的反应性被明确地分为“反应性”和“非反应性”两类环丁烷。因此，用单晶x射线分析确定了二芳基环丁烷的分子结构。虽然环丁烷环的距离和角度相对正常，但在“反应性”环丁烷的情况下，芳基环与环丁烷环的ipso碳和芳基取代碳所涉及的平面之间的扭转角度接近90，而在“非反应性”环丁烷的情况下变化很小。

项目成果

K.Nakabayashi.: Radiat.Rhys.Chem.(1989)

K.Nakabayashi.：Radiat.Rhys.Chem.(1989)

K. Shima: "Molecular Structures of Diarylcyclobutanes Associated with Reactivities in Ring-Cleavage Reactions: Implications of Conformationally Controlled Through-Bond Coupling" Bull. Chem. Soc. Jpn.62. (1989)

K. Shima：“与环裂解反应中的反应性相关的二芳基环丁烷的分子结构：构象控制的键合偶联的含义”公牛。

M.Yasuda.: Bull.Chem.Soc.Jpn.,. 62. (1989)

M.Yasuda.: Bull.Chem.Soc.Jpn.,.

志摩健介: Bull. Chem. Soc. Jpn. 61. (1988)

Kensuke Shima：公牛。Jpn。

K.Nakabayashi: Bull.Chem.Soc.Jpn.,. 62. 96-101 (1989)

K.Nakabayashi：Bull.Chem.Soc.Jpn.,。