Calix[4]arenes with one and two N-linked imidazolium units as precursors of N-heterocyclic carbene complexes. Coordination chemistry and use in Suzuki–Miyaura cross-coupling
作者:Eric Brenner、Dominique Matt、Mickaël Henrion、Matthieu Teci、Loïc Toupet
DOI:10.1039/c1dt10838g
日期:——
The calix[4]arene-imidazolium salts 5-(3-butyl-1-imidazolylium)-25,26,27,28-tetrabenzyloxy-calix[4]arene bromide (cone) (2), and 5,11-bis(3-alkyl-1-imidazolylium)-25,26,27,28-tetrabenzyloxycalix[4]arene diiodide (cone) (R = methyl, 3a; R = n-butyl, 3b) have been synthesised. Reaction of 2 in dioxane with PdCl2 in the presence of CsCO3 and KBr (80 °C, 24 h) gives the carbene complex trans-[PdBr2(calix-monocarbene)2]
杯[4]芳烃-咪唑鎓盐5-(3-丁基-1-咪唑基)-25,26,27,28-四苄氧基-杯[4]芳烃溴化物(圆锥体)(2)和5,11-bis (3-烷基-1- imidazolylium)-25,26,27,28-tetrabenzyloxycalix [4]芳烃二碘化物(锥体)(R =甲基,3A ; R = ñ丁基,3B)已经被合成。2 in反应二恶烷用的PdCl 2在CSCO的存在3和溴化钾(80℃,24小时),得到卡宾络合物的反式- [PDBR 2(杯-monocarbene)2 ](14),含有两个Ñ衍生自-杂环碳烯配体2(产率:63%)。在重复反应吡啶 代替 二恶烷以75%的收率得到混合的吡啶-卡宾配合物反式-[PdBr 2(杯-卡宾)(吡啶)](15)。用[Pd(OAc)2 ]处理双咪唑鎓盐3a得到螯合物,反式-[PdI 2 calix-bis(carbene)}](16),其