Exploiting Synergistic Effects in Organozinc Chemistry for Direct Stereoselective C‐Glycosylation Reactions at Room Temperature
作者:Alberto Hernán‐Gómez、Samantha A. Orr、Marina Uzelac、Alan R. Kennedy、Santiago Barroso、Xavier Jusseau、Sébastien Lemaire、Vittorio Farina、Eva Hevia
DOI:10.1002/anie.201805758
日期:2018.8.13
Pairing a range of bis(aryl) zinc reagents ZnAr2 with the stronger Lewis acidic [(ZnArF2)] (ArF=C6F5), enables highly stereoselective cross‐coupling between glycosyl bromides and ZnAr2 without the use of a transition metal. Reactions occur at room temperature with excellent levels of stereoselectivity, where ZnArF2 acts as a non‐coupling partner although its presence is crucial for the execution of
将一系列双(芳基)锌试剂ZnAr 2与较强的路易斯酸性[(ZnAr F 2)](Ar F = C 6 F 5)配对,可实现糖基溴化物与ZnAr 2之间高度立体选择性的交叉偶联,而无需使用过渡金属。反应在室温下以极好的立体选择性发生,其中ZnAr F 2充当非偶联配偶体,尽管它的存在对于执行C(sp 2)–C(sp 3)键的形成过程。机理研究发现两种锌试剂之间存在独特的协同关系,从而避免了对过渡金属催化或强制反应条件的需求。偶联成功的关键是避免使用相对于二芳基锌化合物(例如THF)的路易斯碱的溶剂。