作者:Jonas Warneke、Markus Plaumann、Ziyan Wang、Esther Böhler、Dorit Kemken、Sørge Kelm、Dieter Leibfritz、Vladimir A. Azov
DOI:10.1016/j.tetlet.2015.01.100
日期:2015.2
the underlying reaction mechanism is discussed. The addition of reactants in the order acryloyl chloride—R-OH—pyridine yields a structure P1, which was tentatively proposed before. However, if the order of reactant addition was changed, that is, R-OH was added to a mixture of acryloyl chloride and pyridine, two new types of pyridinium derivatives (P2 and P3) were observed. Their formation implies the
在吡啶存在下,醇与酰氯的直接酰化反应导致形成意外的吡啶鎓衍生物作为主要产物。尽管几十年前曾简要报道过这种现象,但缺少对中间体和离子产物的详细结构说明。在这项研究中,对形成的吡啶鎓产物进行结构表征,并对潜在的反应机理进行了讨论。以丙烯酰氯-R-OH-吡啶的顺序添加反应物产生结构P1,其是先前尝试性提出的。但是,如果改变了反应物的添加顺序,即将R-OH添加到丙烯酰氯和吡啶的混合物中,这是两种新型的吡啶鎓衍生物(P2和P3)进行观察。它们的形成意味着吡啶与丙烯酰氯的前所未有的β-加成反应,然后是亲核性α-碳的迈克尔加成反应,或者是活化羧基的烷基化。拟议的反应机理得到中间体和产物的详细结构分析的支持。