A General and Practical Palladium-Catalyzed Direct α-Arylation of Amides with Aryl Halides
作者:Bing Zheng、Tiezheng Jia、Patrick J. Walsh
DOI:10.1002/adsc.201300851
日期:2014.1.13
An efficient system for the direct catalytic intermolecular α‐arylation of acetamide derivatives with aryl bromides and chlorides is presented. The palladium catalyst is supported by Kwong’s indole‐based phosphine ligand and provides monoarylated amides in up to 95% yield. Excellent chemoselectivities (>10:1) in the mono‐ and diarylation with aryl bromides were achieved by careful selection of bases
提出了一种用于乙酰胺衍生物与芳基溴化物和氯化物直接催化分子间α-芳基化的有效系统。钯催化剂由 Kwong 的吲哚基膦配体支撑,并以高达 95% 的产率提供单芳基化酰胺。通过仔细选择碱、溶剂和化学计量,在与芳基溴化物的单芳基和二芳基化反应中实现了优异的化学选择性 (>10:1)。在偶联条件下,酰胺的弱酸性 α-质子(p K a高达 35)被叔丁醇锂(LiO- t- Bu)、叔丁醇钠(NaO- t- Bu)或钠双(三甲基甲硅烷基)酰胺[NaN(SiMe 3 ) 2]。