Synthesis of diethyl 2-(aryl)vinylphosphonate by the Heck reaction catalysed by supported palladium catalysts
作者:Jinane Tarabay、Walid Al-Maksoud、Farouk Jaber、Catherine Pinel、Swamy Prakash、Laurent Djakovitch
DOI:10.1016/j.apcata.2010.08.037
日期:2010.11
Interestingly, when using activated aryl bromides the palladium loading could be lowered to only 0.25 mol%. While highly active when coupling aryl iodides (i.e. only 0.15 mol% required), the PdO/SiO2 catalyst was found to be inactive when considering aryl bromides. Deep study of this catalytic material revealed that in the case of aryl bromides, absence of in situ reduction of the catalyst precursor prevents
通过固体物质([Pd(NH 3)4 ] / NaY,Pd / C,PdO / SiO 2)催化的芳基或杂芳基卤化物通过直接Heck偶合反应合成2-(芳基)乙烯基膦酸二乙酯为:报告。优化反应条件后(1.3摩尔%[的Pd(NH 3)4 ] /的NaY,DMF,K 2 CO 3,110-140℃),各种芳基和杂芳基卤化物在从事此反应导致在所有情况下,以良好高产。有趣的是,当使用活化的芳基溴化物时,钯的负载量可降低至仅0.25mol%。虽然偶合芳基碘化物时具有很高的活性(即仅需要0.15 mol%),但PdO / SiO 2当考虑使用芳基溴化物时,发现该催化剂无活性。对这种催化材料的深入研究表明,在芳基溴化物的情况下,不就地还原催化剂前体可防止与后者发生交叉偶联反应。