CH Bond Activation/Borylation of Furans and Thiophenes Catalyzed by a Half-Sandwich Iron N-Heterocyclic Carbene Complex
作者:Tsubasa Hatanaka、Yasuhiro Ohki、Kazuyuki Tatsumi
DOI:10.1002/asia.201000140
日期:——
regioisomers. Treatment of 2 with 2 equiv of HBpin results in the quantitative formation of 2‐boryl‐furan and the borohydride complex [Cp*Fe(LMe)(H2Bpin)] (5). Heating a solution of 5 in the presence of tert‐butylethylene led to the formation of an alkyl complex [Cp*Fe(LMe)CH2CH2tBu] (6), which was found to cleave the CH bond of furan to produce 2. On the basis of these results, a possible catalytic cycle
甲配位不饱和的铁-甲基络合物具有N-杂环卡宾配体,混合[Cp *的Fe(L我)Me](1 ;的Cp * =η 5 -C 5我5,L我= 1,3,4,5-由[Cp * Fe(TMEDA)Cl](TMEDA = N,N,N',N'-四甲基乙二胺)与甲基锂和L Me反应合成。发现配合物1可以激活呋喃,噻吩和苯的CH键,从而生成芳基配合物[Cp * Fe(L Me)(芳基)](芳基= 2-呋喃基(2),2-噻吩基(3),苯基(4))。的C 在叔丁基乙烯和催化量为1(对HBpin为10摩尔%)的存在下,将H键裂解反应应用于呋喃或噻吩与频哪醇硼烷(HBpin)的脱氢偶联。呋喃/噻吩或2-取代的呋喃/噻吩的硼酸酯化分别仅发生在2或5位,而3取代的呋喃/噻吩的硼酸酯化主要发生在5位置并产生区域异构体的混合物。用2当量的HBpin处理2将导致定量生成2硼基呋喃和硼氢化物复合物[Cp * Fe(L Me)(H