Synthesis of Tetraarylallenes via Palladium-Catalyzed Addition-Elimination Reactions of 1,1,3-Triaryl-2-propyn-1-ols with Aryl Iodides
作者:Ming-Jung Wu、Li-Mei Wei、Li-Lan Wei、Wen-Bin Pan
DOI:10.1055/s-2005-872228
日期:——
The palladium-catalyzed reactions of tert-propargylic alcohols with aryl iodides afforded tetraarylallenes in good yields. This reaction involves: (1) oxidative addition of the aryl iodide to Pd(0); (2) arylpalladium intermediate coordination to the carbon-carbon triple bond of the 1,1,3-triaryl-2-propyn-1-ol and subsequent regioselective insertion of the alkynol to form β-hydroxyvinylpalladium species; and (3) β-elimination to produce the tetraarylallenes. Generally, the best results are obtained by employing 5 mol% of Pd(TFA)2, 10 mol% of PPh3, two equivalents of aryl iodide and five equivalents of Et3N in MeCN.
钯催化的叔炔丙醇与芳基碘的反应可以高效地得到四芳基烯,该反应包括以下步骤:(1) 芳基碘的氧化加成到Pd(0);(2) 芳基金属中间体与1,1,3-三芳基-2-丙炔-1-醇的碳-碳三键配位,随后选择性地插入形成β-羟基乙烯基钯物种;(3) β-消去反应生成四芳基烯。通常采用5 mol%的Pd(TFA)2、10 mol%的PPh3、两倍的芳基碘和五倍的Et3N于MeCN溶剂中,可以获得最佳结果。