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。
Studies in organosilicon chemistry. 100. Pentacoordinate allylsiliconates in organic synthesis: synthesis of triethylammonium bis(catecholato)allylsiliconates and selective allylation of aldehydes
A highly enantioselective synthesis of homoallylic amines, using allyltrimethoxysilane under Ag(I) catalytic conditions, has been developed. Among the chiral ligands investigated, a remarkable difference in the resulting Ag(I) complexes was observed. Under mild conditions and low catalyst loadings, homoallylamines were produced in high ee values (up to 80%) and good yields. The methodology can be further
已开发出在 Ag(I) 催化条件下使用烯丙基三甲氧基硅烷的高对映选择性合成高烯丙基胺。在所研究的手性配体中,观察到所得的 Ag(I) 配合物存在显着差异。在温和的条件和低催化剂负载下,以高 ee 值(高达 80%)和良好的产率生产高烯丙胺。该方法可以进一步扩展到醛亚胺的非对映选择性和对映选择性巴豆化。
BINAP/AgOTf/KF/18-Crown-6 as New Bifunctional Catalysts for Asymmetric Sakurai−Hosomi Allylation and Mukaiyama Aldol Reaction
A catalytic amount of KF.18-crown-6 complex is effective as a soluble fluoride source to activate an asymmetric Sakurai-Hosomi allylation with BINAP and silver(I) triflate catalyst. The allylation of a variety of aromatic, alpha,beta-unsaturated and aliphatic aldehydes with allylic trimethoxysilane resulted in high yields and remarkable enantioselectivities. In addition, the asymmetric Mukaiyama-type
Catalytic asymmetric allylation of aldehydes with allylic trimethoxysilanes was achieved with the p-Tol-BINAP small middle dotAgF complex as catalyst [Eq. (a); p-Tol-BINAP=2,2'-bis(di-p-tolylphosphanyl)-1,1'-binaphthyl)]. High anti and enantioselectivities were obtained in the reaction with crotyltrimethoxysilane, irrespective of the configuration at the double bond.
Studies in organosilicon chemistry. 100. Pentacoordinate allylsiliconates in organic synthesis: synthesis of triethylammonium bis(catecholato)allylsiliconates and selective allylation of aldehydes
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。