Highly Efficient Cyclic Dinucleotide Based Artificial Metalloribozymes for Enantioselective Friedel–Crafts Reactions in Water
作者:Changhao Wang、Min Hao、Qianqian Qi、Jingshuang Dang、Xingchen Dong、Shuting Lv、Ling Xiong、Huanhuan Gao、Guoqing Jia、Yashao Chen、Jörg S. Hartig、Can Li
DOI:10.1002/anie.201912962
日期:2020.2.24
construct artificial metalloenzymes (ArMs) for enantioselective catalysis. DNA-based ArMs containing duplex and G-quadruplex scaffolds have been widely investigated, yet RNA-based ArMs are scarce. Here we report that a cyclic dinucleotide of c-di-AMP and Cu2+ ions assemble into an artificialmetalloribozyme (c-di-AMP⋅Cu2+ ) that enables catalysis of enantioselective Friedel-Crafts reactions in aqueous
Enantioselective Friedel−Crafts Alkylations of α,β-Unsaturated 2-Acyl Imidazoles Catalyzed by Bis(oxazolinyl)pyridine−Scandium(III) Triflate Complexes
作者:David A. Evans、Keith R. Fandrick、Hyun-Ji Song
DOI:10.1021/ja052433d
日期:2005.6.1
An enantioselective Friedel−Craftsalkylation with α,β-unsaturated 2-acyl imidazoles and electron-rich aromatic nucleophiles catalyzed by bis(oxazolinyl)pyridine−scandium(III) triflate complexes has been accomplished. These α,β-unsaturated 2-acyl imidazoles are effective electrophiles for the Friedel−Crafts reaction. The resulting adduct 2-acyl imidazole is easily converted to amides, esters, carboxylic
A metal-coordination-based high performance asymmetric catalyst utilizing metal centrochirality as the sole element of chirality is reported. The introduced substitutionallylabile chiral-at-metal octahedral iridium(III) complex exclusively bears achiral ligands and effectively catalyzes the enantioselective Friedel-Crafts addition of indoles to α,β-unsaturated 2-acyl imidazoles (19 examples) with
Enantioselective Friedel−Crafts Alkylations Catalyzed by Bis(oxazolinyl)pyridine−Scandium(III) Triflate Complexes
作者:David A. Evans、Keith R. Fandrick、Hyun-Ji Song、Karl A. Scheidt、Risheng Xu
DOI:10.1021/ja072976i
日期:2007.8.1
The enantioselective Friedel-Crafts addition of a variety of indoles catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes (Sc(III)-pybox) was accomplished utilizing a series of beta-substituted alpha,beta-unsaturated phosphonates and alpha,beta-unsaturated 2-acyl imidazoles. The acyl phosphonate products were efficiently transformed into esters and amides, whereas the acyl imidazole adducts were converted to a broader spectrum of functionalities such as esters, amides, carboxylic acids, ketones, and aldehydes. The sense of stereoinduction and level of enantioselectivity were found to be functions of the size of the substrate employed, the substitution on the ligand, and the catalyst loading. Molecular modeling of the catalyst with the bound substrates was performed based on the crystal structures of the catalyst complexes and the sense of stereoinduction observed in the addition reaction. Nonlinear effects over a range of catalyst concentrations implicate a mononuclear complex as the active catalyst.
Catalytic, Enantioselective Addition of Alkyl Radicals to Alkenes via Visible-Light-Activated Photoredox Catalysis with a Chiral Rhodium Complex
作者:Haohua Huo、Klaus Harms、Eric Meggers
DOI:10.1021/jacs.6b03399
日期:2016.6.8
An efficient enantioselective addition of alkyl radicals, oxidatively generated from organotrifluoroborates, to acceptor-substituted alkenes is catalyzed by a bis-cyclometalated rhodium catalyst (4 mol %) under photoredox conditions. The practical method provides yields up to 97% with excellent enantioselectivities up to 99% ee and can be classified as a redox neutral, electron-transfer-catalyzed reaction