Homolytic substitution at selenium: ring closure of ω-(benzylseleno)alkyl radicals
作者:Lynda J. Benjamin、Carl H. Schiesser、Katarina Sutej
DOI:10.1016/s0040-4020(01)86334-1
日期:1993.3
selenopane in approximately 50% yield. These reactions presumably involve intramolecular free radical homolytic substitution at selenium and appear to proceed readily for both primary and secondary carbon-centered radicals. The 5-(benzylseleno)hex-2-yl radical (1f) appears to ring close without stereoselectivity, to give a 1:1 mixture of - and -2,4-dimethyltetrahydroselenophene, a finding in keeping with
已经研究了一系列ω-(苄基硒代)烷基自由基(1)的闭环。ω-(苄基硒代)链烷酸衍生的硫代异羟肟酸酯在辐射下会平稳分解,并损失二氧化碳,从而以78-95%的收率提供5元和6元含硒环。衍生自7-(苄基硒基)庚酸的硫代异羟肟酸酯以约50%的产率提供7元杂环硒戊烷。这些反应大概涉及硒中的分子内自由基均溶取代,并且对于伯和仲碳中心的自由基似乎都很容易进行。5-(苄基硒基)己-2-基(1f)似乎闭环而没有立体选择性,得到-和1:1的混合物-2,4-二甲基四氢硒化硒,与分子力学(MM2)计算保持一致。