N-杂环卡宾前体咪唑盐 IPr.HCl、IMes.HCl 和 IXy.HCl 的简便合成。
Expedient syntheses of the N-heterocyclic carbene precursor imidazolium salts IPr.HCl, IMes.HCl and IXy.HCl.
机构信息
Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany.
出版信息
Beilstein J Org Chem. 2007 Aug 28;3:22. doi: 10.1186/1860-5397-3-22.
The 1,3-diaryl-imidazolium chlorides IPr.HCl (aryl = 2,6-diisopropylphenyl), IMes.HCl (aryl = 2,4,6-trimethylphenyl) and IXy.HCl (aryl = 2,6-dimethylphenyl), precursors to widely used N-heterocyclic carbene (NHC) ligands and catalysts, were prepared in high yields (81%, 69% and 89%, respectively) by the reaction of 1,4-diaryl-1, 4-diazabutadienes, paraformaldehyde and chlorotrimethylsilane in dilute ethyl acetate solution. A reaction mechanism involving a 1,5-dipolar electrocyclization is proposed.
1,3-二芳基咪唑氯盐 IPr.HCl（芳基= 2,6-二异丙基苯基）、IMes.HCl（芳基= 2,4,6-三甲基苯基）和 IXy.HCl（芳基= 2,6-二甲基苯基）是广泛使用的 N-杂环卡宾（NHC）配体和催化剂的前体，通过 1,4-二芳基-1,4-二氮杂丁二烯、多聚甲醛和三甲基氯硅烷在稀乙酸乙酯溶液中的反应以高产率（分别为 81%、69%和 89%）制备。提出了一种涉及 1,5-偶极环加成的反应机制。
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