80655-81-8Relevant articles and documents
Synthesis and application of N-3,5-dinitrobenzoyl and C3 symmetric diastereomeric chiral stationary phases
Yu, Jeong Jae,Ryoo, Jae Jeong
, p. 587 - 596 (2022/01/20)
Three diastereomeric chiral compounds, namely, (R,R)-(+)-2-amino-1,2-diphenylethanol, (1S,2R)-(+)-2-amino-1,2-diphenylethanol, and (1R,2R)-(+)-1,2-diphenylethylenediamine were used as starting materials for preparing three N-3,5-dinitrobenzoyl derivative
Irradiation-Wavelength Directing Circularly Polarized Luminescence in Self-Organized Helical Superstructures Enabled by Hydrogen-Bonded Chiral Fluorescent Molecular Switches
He, Yanrong,Zhang, Shu,Bisoyi, Hari Krishna,Qiao, Jinghui,Chen, Hong,Gao, JingJing,Guo, Jinbao,Li, Quan
supporting information, p. 27158 - 27163 (2021/10/25)
Two light-driven chiral fluorescent molecular switches, (R,S,R)-switch 1 and (R,S,R)-switch 2, are prepared by means of hydrogen-bonded (H-bonded) assembly of a photoresponsive (S) chiral fluorescent molecule, respectively with a cyano substitution at different positions as an H-bond acceptor and an opposite (R) chiral molecule as an H-bond donor. The resulting two switches exhibit tunable and reversible Z/E photoisomerization irradiated with 450 nm blue and 365 nm UV light. When doped into an achiral liquid crystal, both switches are found to be able to form a CPL tunable luminescent helical superstructure. In contrast to the tunable CPL characteristics of the system incorporating switch 2, exposure of the system incorporating switch 1 to 365 nm and 450 nm radiation can lead to controllable different photostationary CPL behavior, including switching-off and polarization inversion. In addition, optical information coding is demonstrated using the system containing switch 1.
Resolution of Vaulted Biaryl Ligands via Borate Esters of Quinine and Quinidine
Cagnon, Brian R.,Mohammadlou, Aliakbar,Wulff, William D.,Yin, Xiaopeng,Zheng, Li
, p. 10432 - 10450 (2020/09/23)
Given the sudden and unexplained rise in the cost of (+)- A nd (-)-sparteine, an alternative method for the resolution of vaulted biaryls has been developed. This method involves the reaction of a racemic vaulted biaryl ligand with one equivalent of BH3·SMe2 and one equivalent of either quinine or quinidine. A precipitate then forms from the resulting mixture of diastereomeric borates as a result of differential solubilities. Hydrolysis of the precipitate then liberates the (S)-ligand in the case of quinine and the (R)-ligand in the case of quinidine, both with >99% ee. This method has been applied to 16 different vaulted biaryl ligands, including 10 whose preparation is described here for the first time. In addition, proof of principle has been demonstrated for the dynamic thermodynamic resolution of the vaulted biaryl ligands with this method in combination with a nonchiral copper(II) complex that can racemize the ligand.
Novel chiral stationary phases based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin combining cinchona alkaloid moiety
Zhu, Lunan,Zhu, Junchen,Sun, Xiaotong,Wu, Yaling,Wang, Huiying,Cheng, Lingping,Shen, Jiawei,Ke, Yanxiong
, p. 1080 - 1090 (2020/05/25)
Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9-O-(tert-butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
Novel π-expanded chrysene-based axially chiral molecules: 1,1′-bichrysene-2,2′-diols and thiophene analogs
An, Shujie,Liu, Qiancai,Ma, Li,Tang, Guofeng,Zhong, Yaling
, p. 641 - 645 (2020/05/25)
1,1′-Bichrysene-2,2′-diol and its thiophene analogs, 6,6′-biphenanthro-[1,2-b]thiophene-7,7′-diols, as a series of novel π-expanded chrysene-/phenanthro[1,2-b]thiophene-based axially chiral molecules are synthesized from 1,1′-bi-2-naphthols with key steps
Enantioselective Hydroamination of Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer
Demaerel, Joachim,Graff, David E.,Knowles, Robert R.,Roos, Casey B.
supporting information, p. 5974 - 5979 (2020/04/27)
An enantioselective, radical-based method for the intramolecular hydroamination of alkenes with sulfonamides is reported. These reactions are proposed to proceed via N-centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N-H bonds. Noncovalent interactions between the neutral sulfonamidyl radical and a chiral phosphoric acid generated in the PCET event are hypothesized to serve as the basis for asymmetric induction in a subsequent C-N bond forming step, achieving selectivities of up to 98:2 er. These results offer further support for the ability of noncovalent interactions to enforce stereoselectivity in reactions of transient and highly reactive open-shell intermediates.
Enantioselective iron/bisquinolyldiamine ligand‐catalyzed oxidative coupling reaction of 2‐naphthols
Liu, Wen-Bo,Usman, Muhammad,Wu, Lin-Yang
, (2020/02/25)
An iron‐catalyzed asymmetric oxidative homo‐coupling of 2‐naphthols for the synthesis of 1,1′‐Bi‐2‐naphthol (BINOL) derivatives is reported. The coupling reaction provides enantioenriched BINOLs in good yields (up to 99%) and moderate enantioselectivities (up to 81:19 er) using an iron‐complex generated in situ from Fe(ClO4)2 and a bisquinolyldiamine ligand [(1R,2R)‐N1,N2‐di(quinolin‐8‐yl)cyclohexane‐1,2‐diamine, L1]. A number of ligands (L2–L8) and the analogs of L1, with various substituents and chiral backbones, were synthesized and examined in the oxidative coupling reactions.
Ruthenium-Catalyzed Cross-Selective Asymmetric Oxidative Coupling of Arenols
Hayashi, Hiroki,Kim, Chungsik,Uchida, Tatsuya,Ueno, Takamasa
supporting information, (2020/02/26)
(Aqua)ruthenium(salen) complex 1c achieved good to high chemo- A nd enantioselective oxidative cross-coupling of arenols. The catalytic system can be used to selectively produce C1-symmetric bis(arenol)s from the combination of C3- A nd C7-substituted 2-naphthols or phenols even when there is no significant difference in oxidation potential between the cross-coupling partners. This unique cross-selectivity is dominated by steric rather than electronic effects of the arenols and can be controlled by chemoselective single-electron oxidation and oxidative carbon-carbon bond formation.
Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State
Hirose, Daisuke,Isobe, Asahi,Qui?oá, Emilio,Freire, Félix,Maeda, Katsuhiro
, (2019/06/10)
An unprecedented three-state switchable chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) was developed using a helical poly(phenylacetylene) bearing a chiral (R)-α-methoxyphenylacetic acid residue as the pendant (poly-1). The left- and right-handed helical conformations were induced in poly-1-based CSP upon coordination with a catalytic amount of soluble sodium and cesium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate salts (MBArF), respectively, which are soluble in the HPLC conditions [hexane-2-propanol (95:5, v/v)]. The switch between the two different helical states of poly-1 can be easily achieved by rinsing the poly-1-based CSP with MeOH and the subsequent addition of the proper MBArF salt. Using this dynamic helical CSP, we demonstrate how changes on the orientation of the secondary structure of a chiral polymer (right-handed, left-handed, and racemic helices) can alter and even invert the elution order of the enantiomers. This study was done without adding chiral additives or changing the mobile phase, which could produce changes on the retention times and make it more difficult to determine the role of the secondary structure during the chiral recognition process.
Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State
Hirose, Daisuke,Isobe, Asahi,Qui?oá, Emilio,Freire, Félix,Maeda, Katsuhiro
, p. 8592 - 8598 (2019/06/13)
An unprecedented three-state switchable chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) was developed using a helical poly(phenylacetylene) bearing a chiral (R)-α-methoxyphenylacetic acid residue as the pendant (poly-1). The left- and right-handed helical conformations were induced in poly-1-based CSP upon coordination with a catalytic amount of soluble sodium and cesium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate salts (MBArF), respectively, which are soluble in the HPLC conditions [hexane-2-propanol (95:5, v/v)]. The switch between the two different helical states of poly-1 can be easily achieved by rinsing the poly-1-based CSP with MeOH and the subsequent addition of the proper MBArF salt. Using this dynamic helical CSP, we demonstrate how changes on the orientation of the secondary structure of a chiral polymer (right-handed, left-handed, and racemic helices) can alter and even invert the elution order of the enantiomers. This study was done without adding chiral additives or changing the mobile phase, which could produce changes on the retention times and make it more difficult to determine the role of the secondary structure during the chiral recognition process.
