Facile Arylation of Four-Coordinate Boron Halides by Borenium Cation Mediated Boro-desilylation and -destannylation.
Facile Arylation of Four-Coordinate Boron Halides by Borenium Cation Mediated Boro-desilylation and -destannylation.
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DOI：
10.1021/acs.organomet.5b00857
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发表时间：
2015-12-28
期刊：
影响因子：
2.8
通讯作者：
Ingleson MJ
中科院分区：
文献类型：
--
作者：
Crossley DL;Cid J;Curless LD;Turner ML;Ingleson MJ
将AlCl3加到通式(C-N-螯合物)BCl2的四配位的硼烷中，导致卤化物的提取和通式[(C-N-螯合物)BCL]+的三配位的硼阳离子的形成。后者既与芳基锡烷反应，又与芳基硅烷反应，分别通过硼脱硅烷和-脱硅反应生成芳基硼烷。AlCl3的催化量足以实现(C-N-螯合物)BCl2的高产率芳基化反应。在与芳基硅烷的反应中，单芳化或双芳化反应取决于芳基硅烷的亲核性和硼阳离子的亲电性。2-苯基吡啶衍生的硼阳离子的亲电性大于苯并噻二唑类似物，使得亲核性较低的硅烷能够进行硼脱硅化反应，而2-甲基噻吩类化合物可以直接进行亲电的硼化反应。
The addition of AlCl3 to four-coordinate boranes of the general formula (C–N-chelate)BCl2 results in halide abstraction and formation of three-coordinate borenium cations of the general formula [(C–N-chelate)BCl]+. The latter react with both arylstannanes and arylsilanes by boro-destannylation and -desilylation, respectively, to form arylated boranes. Catalytic quantities of AlCl3 were sufficient to effect high-yielding arylation of (C–N-chelate)BCl2. Boro-destannylation is more rapid than boro-desilylation and leads to double arylation at the boron center, whereas in reactions with arylsilanes either single or double arylation occurs dependent on the nucleophilicity of the arylsilane and on the electrophilicity of the borenium cation. The electrophilicity of the borenium cation derived from 2-phenylpyridine was greater than that of the benzothiadiazole analogues, enabling the boro-desilyation of less nucleophilic silanes and the direct electrophilic borylation of 2-methylthiophene.