Phosphole formation by 1,1-carboboration – reactions of bis-alkynyl phosphanes with a frustrated P/B Lewis pair
作者:Annika Klose、Gerald Kehr、Constantin G. Daniliuc、Gerhard Erker
DOI:10.1039/c5dt03055b
日期:——
The arylbis(phenylethynyl)phosphanes 1a,b (aryl = mesityl, 2,4,6-triisopropylphenyl) react with the frustrated P/B Lewis pair (P/B FLP) mes2PCH2CH2B(C6F5)2 (4) to give mixtures of three products; the major products, the phosphole systems 2a,b, are formed by a sequence of 1,1-carboboration reactions. One of the minor compounds (6a,b) is formed by 1,1-carboboration followed by internal 1,2-FLP addition
芳基双(苯基乙炔基)膦1a,b(芳基=甲基1,2,4,6-三异丙基苯基)与受阻的P / B Lewis对(P / B FLP)mes 2 PCH 2 CH 2 B(C 6 F 5)反应2(4)给出三种产物的混合物;主要产物磷脂系统2a,b是通过1,1-碳硼化反应序列形成的。一种次要化合物(6a,b)是通过1,1-碳硼化,然后向剩余的C C三键内部加成1,2-FLP形成的。产品混合物中的其他次要化合物(5a,b通过将1,2-FLP加到起始原料的一个炔基部分中得到)。通过X射线衍射表征产物5a,6b和磷脂2a的衍生物(通过与末端炔烃的FLP反应形成)。芳基双(戊炔基)膦1c,d与FLP 4的反应选择性地产生相应的–B(C 6 F 5)2 / –CH 2 CH 2 –Pmes 2取代的磷脂2c,d以高产率分离为橙色固体。通过NMR光谱检测到两个体系的开环和闭环P⋯B FLP异构体之间都存在快速强烈的温度依赖性平衡。