Novel Homologation Reaction of Arylzincates Bearing a Leaving Group at the Ortho and Meta Positions.
Novel Homologation Reaction of Arylzincates Bearing a Leaving Group at the Ortho and Meta Positions.
复制标题
在邻位和间位带有离去基团的芳基锌酸盐的新型同系反应。
DOI：
10.1021/jo990937m
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
A. Oku
中科院分区：
文献类型：
--
作者：
T. Harada;M. Chiba;A. Oku
通过碘代芳基磺酸盐与Bu（3）ZnLi的碘/锌交换反应，合成了在邻位、Meta位和帕拉带有离去基团的芳基锌酸盐，并通过水解和碘处理后的产物分析研究了它们的反应活性.邻碘苯基三氟甲磺酸盐与甲苯磺酸盐的锌酸盐发生同系化反应生成邻丁基苯基锌。邻苄基作为反应中间体的三取代锌酸盐的区域选择性的缺乏证明。从间碘苯基三氟甲磺酸盐衍生的锌酸盐也经历了同系物化，导致间丁基苯基锌物种。在区域异构的三取代碘苯基三氟甲磺酸酯的反应中观察到的类似的产物比率以及自由基反应副产物的形成表明了间苯炔中间体的参与。对-（三氟甲磺酰氧基）苯基锌酸酯在室温下是热稳定的;未观察到对苯炔的生成。
Arylzincates bearing a leaving group at the ortho, meta, and para positions were generated by iodine/zinc exchange reaction of the corresponding iodoaryl sulfonates with Bu(3)ZnLi, and their reactivity was investigated via product analysis after hydrolysis and treatment with iodine. Zincates derived from o-iodophenyl triflates and tosylate underwent homologation reaction to give o-butylphenylzinc species. o-Benzyne as an intermediate of the reaction was demonstrated by the lack of regioselectivity for trisubstituted zincates. Zincates derived from m-iodophenyl triflates also underwent homologation leading to m-butylphenylzinc species. Similar product ratios observed in the reactions of regioisomeric trisubstituted iodophenyl triflates as well as the formation of radical reaction byproducts suggested the involvement of m-benzyne intermediate. p-(Trifluoromethanesulfonyloxy)phenylzincate was thermally stable at room temperature; generation of p-benzyne was not observed.