A Palladium-Catalyzed Multicomponent Synthesis of Imidazolinium Salts and Imidazolines from Imines, Acid Chlorides, and Carbon Monoxide
作者:Kraig Worrall、Boran Xu、Sébastien Bontemps、Bruce A. Arndtsen
DOI:10.1021/jo101858d
日期:2011.1.7
imidazolinium carboxylates and imidazolines is described. The palladium catalyst [Pd(CH(R1)N(R2)COR3)Cl]2, or [Pd(allyl)Cl]2, with P(t-Bu)2(2-biphenyl) can mediate the simultaneous coupling of two imines, acid chloride, and carbon monoxide into substituted imidazolinium carboxylates within hours under mild conditions (45 °C, 4 atm of CO). The reaction proceeds in good yield with aryl-, heteroaryl-, and alkyl-substituted
描述了钯催化的羧酸咪唑啉和咪唑啉的多组分合成。钯催化剂[Pd(CH(R 1)N(R 2)COR 3)Cl] 2或[Pd(烯丙基)Cl] 2,具有P(t- Bu)2(2-联苯)可以在温和条件下(45°C,4 atm CO)在数小时内将两个亚胺,酰氯和一氧化碳同时偶联到取代的咪唑啉代羧酸盐中。用芳基,杂芳基和烷基取代的酰氯,以及各种官能化的亚胺,反应以高收率进行。咪唑啉是通过最初生成的Münchnone中间体形成的,然后将它们与原位生成的质子化的亚胺环加成。胺碱的添加可以阻止Münchnone形成时的催化作用,从而允许随后的第二个亚胺的环加成反应。后者提供了一种复杂的,多取代的咪唑啉鎓羧酸盐的组装方法,并且可以独立控制所有五个取代基。