An unprecedented iron-catalyzed cross-coupling of primary and secondary alkyl Grignard reagents with non-activated aryl chlorides
作者:Marc C. Perry、Amber N. Gillett、Tyler C. Law
DOI:10.1016/j.tetlet.2012.06.048
日期:2012.8
The use of N-heterocyclic carbene ligands in the iron-catalyzed cross-coupling of alkyl Grignards has allowed, for the first time, coupling of non-activated, electron rich aryl chlorides. Surprisingly, the tetrahydrate of FeCl2 was found to be a better pre-catalyst than anhydrous FeCl2. Primary Grignard reagents coupled in excellent yields while secondary Grignard reagents coupled in modest yields
在烷基格氏试剂的铁催化的交叉偶联中使用N杂环卡宾配体,首次使未活化的富电子芳基氯化物偶联。令人惊讶的是,发现四水合FeCl 2比无水FeCl 2有更好的预催化剂。初级格氏试剂的产率很高,而二级格氏试剂的产率很适中。除所需产物外,使用无环二次格氏试剂还导致了异构体的形成。这些异构产物是通过可逆的β-氢消除形成的,表明交叉偶联通过离子途径进行。