Stereocontrolled synthesis of tertiary silanes via optically pure 1,3,2-oxazasilolidine derivatives
摘要:
Optically pure 1,3,2-oxazasilolidine derivatives were synthesized from a chiral 1,2-amino alcohol. These heterocyclic compounds containing a stereogenic silicon atom produced tertiary silanes with excellent optical purity through successive reactions with Grignard reagents and diisobutylaluminum hydride. Stereochemical course of the reactions of the oxazasilolidine at the chiral silicon atom was elucidated based on the absolute configurations of the products and the substrate which were determined by chiral HPLC and X-ray crystallographic analyses. (C) 2009 Elsevier B. V. All rights reserved.
对映体富集的α-羟基酰胺和β-氨基醇的合成已通过用氢硅烷将α-酮酰胺对映选择性还原而完成。通过使用(EtO)3 SiH作为还原剂,在手性Cu II /(S)-DTBM-SEGPHOS催化剂存在下还原了一系列α-酮酰胺,得到了具有出色对映选择性的相应光学活性α-羟基酰胺。此外,使用相同的手性铜催化剂,然后在(EtO)3 SiH存在下,用四正丁基氟化铵(TBAF)催化剂,一锅完全还原了α-酮酰胺的酮基和酰胺基。相应的手性β-氨基醇衍生物。
A number of opticallyactive amino alcohols were synthesized by direct asymmetric transfer hydrogenation of the corresponding amino ketones with good-to-high enantiomeric excesses (up to 95%) and excellent yields (up to 93% ). When the range of substrates was broadened to include α-sulfonamido ketones or α-keto sulfones, the corresponding products were obtained with 100% enantiomeric excesses. The
Multistep Organic Transformations over Base-Rhodium/Diamine-Bifunctionalized Mesostructured Silica Nanoparticles
作者:Hang Liao、Yajie Chou、Yu Wang、Han Zhang、Tanyu Cheng、Guohua Liu
DOI:10.1002/cctc.201700436
日期:2017.8.23
enantioselectivities, in which the asymmetric transfer hydrogenation of α-haloketones followed by epoxidation provides various chiral aryloxiranes, and the amination of α-haloketones with anilines followed by asymmetric transfer hydrogenation produces various β-aminoalcohols. Furthermore, the catalyst can be recovered and recycled for seven times without a loss of catalytic activity, which is an attractive
在非均相不对称催化中,在一个介孔二氧化硅中将多种催化官能团作为催化剂用于环境友好介质中的多步对映选择性有机转化是一个重大挑战。在本文中,我们采取了BF的优点4 -阴离子氢键策略来锚手性阳离子铑/二胺碱官能化的介孔结构的二氧化硅纳米粒子内复杂方便地构造一个双功能的非均相催化剂。固态13 C NMR光谱揭示了定义明确的手性Rh /二胺活性物质,我们使用了XRD,N 2吸附-解吸和电子显微镜揭示有序的介观结构。二氧化硅纳米粒子中双官能团的结合实现了两种高效的对映选择性有机转化,具有高收率和对映选择性,其中α-卤代酮的不对称转移加氢,然后环氧化提供了各种手性芳基氧杂环戊烷,以及随后将α-卤代酮与苯胺胺化通过不对称转移氢化产生各种β-氨基醇。此外,该催化剂可被回收和再循环七次而不会损失催化活性,这对于可持续的良性过程中的多步有机转化而言是一个吸引人的特征。
Kinetic resolution of <i>N</i>-aryl β-amino alcohols <i>via</i> asymmetric aminations of anilines
作者:Zheng Guo、Jinglei Xie、Tao Hu、Yunrong Chen、Houchao Tao、Xiaoyu Yang
DOI:10.1039/d1cc03117a
日期:——
An efficientkineticresolution of N-aryl β-amino alcohols has been developed via asymmetric para-aminations of anilines with azodicarboxylates enabled by chiral phosphoric acid catalysis. Broad substrate scope and high kineticresolution performances were afforded with this method. Control experiments supported the critical roles of the NH and OH group in these reactions.
Ru-Tethered (<i>R,R</i>)-TsDPEN with DMAB as an efficient catalytic system for high enantioselective one-pot synthesis of chiral β-aminol <i>via</i> asymmetric transfer hydrogenation
作者:Ashish A. Mishra、Bhalchandra M. Bhanage
DOI:10.1039/d0nj06108e
日期:——
active α-substituted alcohols and its derivatives from α-bromo ketones in the presence of dimethylamine borane (DMAB) as the hydrogen source. Various Ru-chiral catalysts have been screened and the methodology proceeded via a (R,R) Ru-tethered TsDPEN catalyst through asymmetric transfer hydrogenation (ATH) of the in-situ formed ketones to the corresponding chiral β-aminol product. Thus, the Ru-tethered
The present invention relates to a crystalline metal organic framework which comprises repeating units of formula (RR)-(IA)or (SS)-(IA)or (RS)-(IA) or (SR)-(IA); or alternatively of formula (RR)-(IB) or (SS)-(IB) or (RS)-(IB) or (SR)-(IB) and acomposition containing it. It also relates to processes for their preparation and theiruses as a separation agent and as a catalyst.