Oxidant-free direct coupling of internal alkynes and 2-alkylpyridine via double C-H activations by alkylhafnium complexes.
Oxidant-free direct coupling of internal alkynes and 2-alkylpyridine via double C-H activations by alkylhafnium complexes.
复制标题
DOI：
10.1021/ja1100118
复制
发表时间：
2011-02
影响因子：
15
通讯作者：
H. Tsurugi;Koji Yamamoto;K. Mashima
中科院分区：
文献类型：
--
作者：
H. Tsurugi;Koji Yamamoto;K. Mashima
我们开发了一种新的无氧化剂的2，6-二甲基吡啶和内炔的直接交叉偶联反应，导致五元碳环化合物介导的非茂金属阳离子铪烷基络合物。偶联反应的机理研究表明，该反应首先通过σ-键复分解活化C（sp（3））-H键，之后配位不饱和铪中心介导进一步的插入、迁移和β-H消除反应，从容易获得的底物得到五元碳环。
We have developed a novel oxidant-free direct cross-coupling reaction of 2,6-lutidine and internal alkynes leading to five-membered carbocyclic compounds mediated by nonmetallocene cationic hafnium alkyl complexes. Mechanistic studies of the coupling reaction showed that the reaction begins with C(sp(3))-H bond activation via σ-bond metathesis, after which the coordinatively unsaturated hafnium center mediates further insertion, migration, and β-H elimination reactions to give five-membered carbocycles from readily available substrates.