Synthesis of Silylboronic Esters Functionalized on Silicon
摘要:
New silylpinacolboranes bearing chloro, fluoro, alkoxy, and dialkylamino groups on silicon were synthesized in high yields via derivatization of [(diethylamino)diphenylsilyl]pinacolborane, which was prepared by reaction of [(diethylamino)diphenylsilyl]lithium with (isopropoxy)pinacolborane, and (chlorodimethylsilyl)pinacolborane, prepared by reaction of (dimethylphenylsilyl)pinacolborane with hydrogen chloride in the presence of a catalytic amount of aluminum chloride.
2 + 1] cycloaddition takes place in the rhodium-catalyzed reaction of 1,6-enynes with borylsilanes bearing an alkoxy group on the silicon atoms, which react as synthetic equivalents of silylene. The reaction proceeds efficiently in 1,2-dichloroethane at 80–110 °C in the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM) as a ligand to afford 1-silacyclopent-2-enes in good to
Copper-catalyzed silafunctionalization of alkynes using a silylboronic ester as a silicon source has recently progressed rapidly. Generally, the reaction affords a product with cis-stereoselectivity. We herein describe trans-selective 1,2-addition of silylboronic esters to internal arylalkynes, which was promoted efficiently by the CuOt-Bu/RCy2P/NaOt-Bu catalysts. Moreover, we report a stereochemical
使用甲硅烷基硼酸酯作为硅源的炔烃的铜催化的硅烷基化最近进展迅速。通常,该反应提供具有顺式-立体选择性的产物。我们在本文中描述了甲硅烷基硼酸酯向内部芳基炔烃的反式选择性1,2-加成,其通过CuO t -Bu / RCy 2 P / NaO t -Bu催化剂有效地促进。此外,我们报道了在包括环己烷在内的烃类溶剂中,Me 2(i -PrO)Si–B(pin)的反应中立体化学转换为顺式加成。
<i>Anti</i>-Selective Vicinal Silaboration and Diboration of Alkynoates through Phosphine Organocatalysis
作者:Kazunori Nagao、Hirohisa Ohmiya、Masaya Sawamura
DOI:10.1021/acs.orglett.5b00305
日期:2015.3.6
Trialkylphosphine organocatalysts have enabled anti-selective vicinal silaboration and diboration of the C-C triple bond in alkynoates to produce beta-boryl-alpha-silyl acrylates and alpha,beta-diboryl acrylates, respectively. The anti stereoselectivity was complete and robust. A variety of functional groups were tolerated in the alkynoates. The two vicinally installed heteroatom substituents of the beta-boryl-alpha-silyl acrylates and alpha,beta-diboryl acrylates could be differentiated and transformed in a stepwise manner, allowing the synthesis of a diverse array of unsymmetrical tetrasubstituted alkenes.