Supramolecular chiral dendritic monophosphites assembled by hydrogen bonding and their use in the Rh-catalyzed asymmetric hydrogenation
作者:Yong Li、Yan-Mei He、Zhi-Wei Li、Feng Zhang、Qing-Hua Fan
DOI:10.1039/b823047a
日期:——
A new type of supramolecular chiral dendritic monophosphite ligands has been prepared via a hydrogen-bonding assembly. The Rh complexes of these supramolecular ligands have been successfully applied in the asymmetric hydrogenation of enamides and dehydroamino acid derivatives with good enantioselectivities, which are comparable to those obtained from the free monophosphite ligands. The supramolecular catalyst could be easily recycled viasolvent precipitation.
Conjugate addition of potassiumtrifluoro(organo)borates 2 to dehydroalanine derivatives 1, mediated by a chiral rhodium catalyst and in situ enantioselective protonation, afforded straightforward access to a variety of protected alpha-amino esters 3 with high yields and enantiomeric excesses up to 95%. Among the tested chiral ligands and proton sources, Binap, in combination with guaiacol (2-methoxyphenol)
Concise synthesis and applications of enantiopure spirobiphenoxasilin-diol and its related chiral ligands
作者:Lei Yang、Wen-Qiang Xu、Tao Liu、Yichen Wu、Biqin Wang、Peng Wang
DOI:10.1039/d1cc05576c
日期:——
for asymmetriccatalysis. Herein, we report the concise synthesis of a Si-centered spirocyclic skeleton, spirobiphenoxasilin-diol (SPOSiOL), and its derived chiral ligands. Using the chemical resolution method, the optical SPOSiOL could be obtained in high yield on a gram scale. Preliminary studies indicated that this ligand scaffold has great potential in transition metal-catalyzed asymmetric reactions
手性配体和催化剂发现的手性结构的开发对于不对称催化至关重要。在此,我们报告了以 Si 为中心的螺环骨架、SPirobiphenoxasilin-diol (SPOSiOL) 及其衍生手性配体的简明合成。使用化学拆分方法,可以在克级以高产率获得光学 SPOSiOL。初步研究表明,该配体支架在过渡金属催化的不对称反应中具有巨大潜力。这一发现进一步强调了以 Si 为中心的螺环支架在不对称催化中具有重要价值。
Practical by Ligand Design: A New Class of Monodentate Phosphoramidite Ligands for Rhodium-Catalyzed Enantioselective Hydrogenations
作者:Baoguo Zhao、Zheng Wang、Kuiling Ding
DOI:10.1002/adsc.200606013
日期:2006.6
new class of low-cost and easy-to-prepare monodentate phosphoramidite ligands (CydamPhos) has been developed from readily accessible and cheap trans-1,2-diaminocyclohexane as starting material through a three-step transformation. This type of ligands exhibited excellent enantioseletivities and high activities in rhodium(I)-catalyzed asymmetric hydrogenations of dehydro-α-amino acid methyl esters 9 (ee:
Asymmetric Synthesis XXVIII: Novel Chiral Aminophosphine Phosphinite Ligand and Its Application in Homogenous Catalytic Asymmetric Hydrogenation of Dehydroamino Acid Derivatives
作者:Aiqiao Mi、Rongliang Lou、Yaozhong Jiang、Jingen Deng、Yong Qin、Fangmin Fu、Zhi Li、Wenhao Hu、Albert S. C. Chan
DOI:10.1055/s-1998-1821
日期:1998.8
Novel chiral aminophosphine phosphinite, DPAMPP was designed and synthesized from (1S,2R)-1,2-diphenyl-2-aminomethanol. Its cationic rhodium complex has been found to be an excellent catalyst for enantioselective hydrogenation of dehydroamino acids (more than 95.0% e.e.).