已开发出一种广泛使用的五元杂芳烃和末端炔烃的氧化偶合,它使用钯盐和银盐的组合。在合适的条件下,咪唑和苯并咪唑(在类似的先前报道的氧化偶合条件下反应迟缓)以及咪唑并[1,5- a ]吡啶,恶唑,苯并恶唑,噻唑和苯并噻唑可以被炔基化。另外,在反应条件下,底物上的溴原子是完整的,并且根本不发生常规的Sonogashira偶联。掌握了这些反应活性,即可得到明确定义的合成咪唑的合成路线[1,5- a含有两个不同炔基的对吡啶和噻唑的制备方法很简单。此外,不仅获得的1,3-双(芳基乙炔基)咪唑基[1,5]的C1上,而且C3炔基上的芳烃基团的荧光波长与Hammett取代基常数之间也存在线性关系。 -一]吡啶。
Dehydrogenative and decarboxylative C–H alkynylation of heteroarenes catalyzed by Pd(II)–carbene complex
作者:Thupakula Parsharamulu、Police Vishnuvardhan Reddy、Pravin R. Likhar、Mannepalli Lakshmi Kantam
DOI:10.1016/j.tet.2015.02.020
日期:2015.4
The direct alkynylation of heteroarenes was accomplished with easily prepared Pd(II) carbene complex (Pd Cat.) by two complementary strategies. Pd Cat. catalysed cross-dehydrogenative coupling of terminal alkynes with heteroarenes was achieved in the first method and decarboxylative coupling of aryl propiolic acids with heteroarenes was investigated in the second method. Both the methodologies tolerate a broad variety of heteroarenes that include benzoxazoles, benzothiazoles, imidazole and benzimidazoles. (C) 2015 Elsevier Ltd. All rights reserved.