Stereoselective Synthesis of Highly Enantioenriched (E)-Allylsilanes by Palladium-Catalyzed Intramolecular Bis-Silylation: 1,3-Chirality Transfer and Enantioenrichment via Dimer Formation
作者:Michinori Suginome、Taisuke Iwanami、Yutaka Ohmori、Akira Matsumoto、Yoshihiko Ito
DOI:10.1002/chem.200401031
日期:2005.1
Highly enantioenriched (E)-allylsilanes have been synthesized from optically active allylic alcohols on the basis of Pd-catalyzed intramolecular bis-silylation followed by highly stereospecific Si-O elimination reactions. The method involves three steps: 1) O-disilanylation of the allylic alcohols with chlorodisilanes, 2) intramolecular bis-silylation in the presence of a 1,1,3,3-tetramethylbutyl
基于Pd催化的分子内双甲硅烷基化,然后进行高度立体有规的Si-O消除反应,由旋光性烯丙基醇合成了高度对映体富集的(E)-烯丙基硅烷。该方法包括三个步骤:1)烯丙基醇与氯乙硅烷的O-二甲硅烷基化,2)在1,1,3,3-四甲基丁基异氰化物/ [Pd(acac)2](acac =乙酰丙酮化物)催化剂在110摄氏度,和3)用有机锂试剂处理反应混合物。通过C = C键的移位,起始烯丙基醇的对映体纯度几乎完全被保留,从而进行整个转化。例如,(R)-(E)-3-癸烯-2-醇(99.6-99.7%ee)产生的(S)-(E)-4-(有机甲硅烷基)-2-癸烯的ee为98.8-99.4%各种甲硅烷基,包括Me3Si,Me2PhSi,tBuMe2Si,Et3Si和iPr3Si。在双甲硅烷基化步骤中,最初形成的反式1,2-氧杂环丁烷立即二聚以立体选择性地生成1,5-二氧杂-2,6-二硅环辛烷,通过在70°C下进行反