A general method for the preparation of cyclopropanes is reported. Triplet-photosensitized reactions of a series of cyclobutanones give cyclopropanes as the major product. Part 1 describes the synthesis of substituted cyclobutanones used in this study. In Part 2, the photo-reactions of cyclobutanones are reported. Triplet-sensitized reactions of cyclobutanones using acetone as a sensitizer give cyclopropanes as the major non-polar products. The extent of photodecarbonylation seems to be dependent on α-substitution. Electron-donating groups promote decarbonylation while electron-withdrawing groups favour cycloelimination.Key words: photodecarbonylation, cyclobutanones, cyclopropanes, triplet-sensitization.
报道了一种制备环丙烷的通用方法。一系列环丁酮的三重态光敏反应产生环丙烷作为主要产物。第一部分描述了在本研究中使用的取代环丁酮的合成。在第二部分中,报道了环丁酮的光反应。使用丙酮作为光敏剂的环丁酮的三重态敏化反应产生环丙烷作为主要的非极性产物。光去羰基化的程度似乎取决于α-取代。电子给予基团促进去羰基化,而电子吸引基团有利于环消除。关键词:光去羰基化,环丁酮,环丙烷,三重态敏化。