Stereochemicalaspect of asymmetric Ag-catalyzed Hosomi-Sakurai reaction with ketones has been investigated. Several allyltrimethoxysilanes have been synthesized and used for the asymmetric reaction. Remarkably, among several possible diastereomers only two are generated with high levels of diastereo- and enantioselectivities. Based on the observations for different allyltimethoxysilanes, we hypothesize
已经研究了不对称 Ag 催化的 Hosomi-Sakurai 与酮反应的立体化学方面。已经合成了几种烯丙基三甲氧基硅烷并用于不对称反应。值得注意的是,在几种可能的非对映异构体中,只有两种具有高水平的非对映选择性和对映选择性。基于对不同烯丙基二甲氧基硅烷的观察,我们假设形成单一烯丙基银物质,该物质与酮发生加成。
Effect of substituent on reactions remote from silicon: regioselective .alpha.-alkylation of .alpha.-silylallyl carbanions
作者:Raymond F. Horvath、Tak Hang Chan
DOI:10.1021/jo00263a012
日期:1989.1
HORVATH, RAYMOND F.;CHAN, TAK HANG, J. ORG. CHEM., 54,(1989) N, C. 317-327
作者:HORVATH, RAYMOND F.、CHAN, TAK HANG
DOI:——
日期:——
Unusual Carbon−Carbon Bond Formations between Allylboronates and Acetals or Ketals Catalyzed by a Peculiar Indium(I) Lewis Acid
作者:Uwe Schneider、Hai T. Dao、Shu̅ Kobayashi
DOI:10.1021/ol100450s
日期:2010.6.4
mechanism is proposed in which a single InI center acts as a dual catalyst to activate both reagents sequentially. Contrary to the classic γ-selectivity of allylsilanes (Hosomi−Sakuraireaction), this InI-catalyzed boronovariant displays distinct α-selectivity. Substrate scope and functional group tolerance proved to be excellent.
在I OTf中,已发现它是有效的路易斯酸催化剂,用于用烯丙基硼酸酯对乙缩醛或缩酮进行前所未有的亲核取代。提出了一种超金属化S N 1机制,其中单个In I中心充当双重催化剂,以依次激活两种试剂。与烯丙基硅烷的经典γ选择性(Hosomi-Sakurai反应)相反,此In I催化的硼烷变体表现出独特的α选择性。底物范围和官能团耐受性被证明是极好的。