Free Radical and Photochemical Reactions of OrganophosphorusSystems

有机化学和高分子化学项目的这项拨款支持W.本特鲁德教授的研究，该研究旨在阐明以自由基为反应中间体的有机磷体系的化学反应机理。这项工作的重要性有两个原因：(1)它将提供对某些含磷有机分子在光吸收和其他激发事件的激发下反应生成不成对的电子中间体(自由基)的逐步过程的理解；(2)这些反应中的许多可以用作制备敏感化合物的合成方法。计划研究有机磷分子的自由基和光化学反应。将继续进行新的调查和在上一批赠款期间发现的反应的新方面。一个主要的主题是设计和研究真正的双自由基或类双自由基电子激发态在分子内或分子间过程中与三价磷反应的反应体系。这些系统的机械性、探索性的新反应和合成方面将被检验。这项工作中包括的反应物包括光激发烯、炔、烯、羰基和硫代羰基，以及Norrish I型光裂解反应和偶氮化合物的光解反应产生的双自由基。此外，还将研究捕获完整的磷酰基自由基的新反应。对本特鲁德实验室新发现的亚磷酸苄酯分子内光-Arbuzov反应的机理和合成应用进行了探讨。还需要深入研究的是苯基亚磷酸盐在醇存在下的光解。将评估其使用其他生色团和离开基团的机理和一般性。

This grant in the Organic and Macromolecular Chemistry Program supports research by Prof. W. Bentrude, which aims at elucidating mechanisms in chemical reactions of organophosphorus systems with free radicals as reaction intermediates. This work is important for two reasons: (1) It will provide understanding of the step- by-step processes by which certain phosphorus-containing organic molecules react to generate unpaired-electron-intermediates (free radicals) when excited by light absorption and other energizing events; and (2) many of these reactions may be used as synthetic methods for preparation of sensitive compounds. Studies of both free radical and photochemical reactions of organophosphorus molecules are planned. Both new investigations and new aspects of reactions discovered in the previous grant period will be pursued. A major theme is the design and investigation of reaction systems in which true biradicals or biradical-like electronic excited states react with tricovalent phosphorus in intra- or intermolecular processes. Mechanistic, exploratory new-reaction, and synthetic aspects of these systems are to be examined. Reactants included in this work are photoexcited alkenes, alkynes, allenes, carbonyls, and thiocarbonyls, along with biradicals from Norrish Type I photocleavage reactions and the photolyses of azo compounds. In addition, new reactions in which intact phosphoranyl radicals are trapped will be studied. The mechanistic aspects and synthetic applications of the intramolecular photo-Arbuzov reaction of benzyl phosphites, newly discovered in Bentrude's laboratory, will be explored. Also to be thoroughly studied is the photosolvolysis of benzyl phosphites in the presence of alcohols. Its mechanism and generality using other chromophores and leaving groups will be assessed.