Easy Access to Esters with a Benzylic Quaternary Carbon Center from Diallyl Malonates by Palladium-Catalyzed Decarboxylative Allylation
作者:Daisuke Imao、Akihiro Itoi、Asako Yamazaki、Masamichi Shirakura、Ryota Ohtoshi、Kenta Ogata、Yohki Ohmori、Tetsuo Ohta、Yoshihiko Ito
DOI:10.1021/jo0621569
日期:2007.3.1
used did not affect the catalytic cycle. Catalysis in [bmim][BF4], a well-known ionic liquid, was inhibited as a result of formation of a hydrogen bond between a carboxylate anion and a [bmim]+ cation; however, the reaction in [bdmim][BF4], in which the acidic proton of [bmim][BF4] was replaced with a methyl group, proceeded smoothly. The catalytic mechanism was investigated using a tetradeuterated
在温和条件下,2-烷基-2-芳基丙二酸二烯丙基酯迅速经历了钯催化的脱羧烯丙基化。相反,在相同条件下,没有与烯丙基2,2-二烷基丙二酸酯发生反应。发现给电子的膦配体对于该反应是至关重要的。所使用的大多数溶剂不影响催化循环。由于在羧酸根阴离子和[bmim] +阳离子之间形成氢键,因此抑制了在众所周知的离子液体[bmim] [BF 4 ]中的催化。但是,在[bdmim] [BF 4 ]中的反应,其中[bmim] [BF 4用甲基取代],进行顺利。使用四氘代底物和酶促合成的对映体富集的2-甲基-2-苯基丙二酸甲基烯丙酯,研究了催化机理。发现甚至缺乏电子的亚磷酸酯配体对于催化烯丙基2-甲基-2-(2-或4-硝基苯基)丙二酸酯也具有活性。