Cyclizations versus rearrangements in the reactions of some epoxyolefins with Lewis acids†
作者:Lars Pettersson、Torbjörn Frejd
DOI:10.1039/b010101j
日期:——
Treatment of various substituted epoxyolefins A: with BF3·OEt2 and other reagents that could be expected to induce carbocyclization to give cyclohexanes was investigated. It turned out that the general reaction of these systems was the epoxide to ketone rearrangement, while the carbocyclization was only a rare event. Only substrates carrying the allylsilane grouping underwent carbocyclization and in addition the protecting groups and the stereochemistry of the system had a decisive influence on whether ring closure or rearrangement were to take place.
对各种取代环氧烯烃A与BF3·OEt2及其他可能诱导碳环化反应生成环己烷的试剂进行了研究。结果表明,这些体系的一般反应是环氧化物转变为酮的重排,而碳环化仅是一个罕见事件。只有携带烯丙基硅烷基团的底物经历了碳环化,此外,保护基团和体系的立体化学对环闭合或重排的发生有决定性影响。