39262-22-1Relevant academic research and scientific papers
Solid Polymer Electrolytes Comprising Camphor-Derived Chiral Salts for Solid-State Batteries
Armand, Michel,Johansson, Patrik,Lobato, Elias,Martinez-Ibaez, María,Qiao, Lixin,Sanchez-Diez, Eduardo,Santiago, Alexander,Treskow, Marcel,Zhang, Heng,Zhang, Yan
, (2020/10/05)
Solid polymer electrolytes (SPEs) with both excellent processability and flexibility have been deemed as an auspicious alternative to develop safe solid-state lithium metal (Li°) batteries (SSLMBs). The electrochemical performance of SSLMBs is ultimately associated with the nature of the Li-salt anion and the widely used bis(trifluoromethanesulfonyl)imide anion (TFSI) is "slippery"due to its perfluorinated nature and therefore highly mobile, which leads to severe polarization upon battery cell charge/discharge cycles. In this work, we report on a new type of chiral salts, synthesized from commercially available camphorsulfonic acid, used in poly(ethylene oxide) (PEO)-based SPEs. The impact of the chirality of the anions on the fundamental physical properties of the SPEs is extensively studied in terms of thermal stability, phase transition and ionic conductivity, etc. We demonstrate that the resulting SPEs exhibit agreeable ionic conductivities (ca. 104 S cm1) accompanied by high cation transference numbers (ca. 0.5) at 70 °C. Whether either the R or the S enantiomers are used the ion transport properties are the same, as expected, but rather surprisingly the artificial racemic mixture is within the errors of the measurements just as conductive. We discuss how this opens a new avenue to design novel salts for reaching high-performant SSLMBs.
Ligand dependence of the synthetic approach and chiroptical properties of a magic cluster protected with a bicyclic chiral thiolate
Knoppe, Stefan,Kothalawala, Nuwan,Jupally, Vijay Reddy,Dass, Amala,Buergi, Thomas
supporting information; experimental part, p. 4630 - 4632 (2012/06/15)
Chiral gold clusters stabilised by enantiopure thiolates were prepared, size-selected and characterised by circular dichroism and mass spectrometry. The product distribution is found to be ligand dependent. Au25 clusters protected with camphorthiol show clear resemblance of their chiroptical properties with their glutathionate analogue. The Royal Society of Chemistry 2012.
The Ru-catalyzed enantioselective preparation of chiral halohydrins and their application in the synthesis of (R)-clorprenaline and (S)-sotalol
Lu, Chuanjun,Luo, Zonghua,Huang, Ling,Li, Xingshu
experimental part, p. 722 - 727 (2011/08/06)
The asymmetric transfer hydrogenation of a series of halo-substituted aryl methyl ketones, including those substituted in both α-methyl and aryl rings, was studied for the preparation of chiral halohydrins. Up to 99.7% ee was obtained with 2-chloro-1-(2-chlorophenyl)ethanone as the substrate and Ru-CsDPEN as the catalyst in an HCOONa/H2O system. (R)-Clorprenaline, a drug used in the treatment of respiratory disorders, such as bronchitis and asthma, and (S)-sotalol, a class-III antiarrhythmic compound, were prepared with these chiral halohydrins.
PROCESS FOR THE PREPARATION OF OPTICALLY ACTIVE (4E)-5- HALO-2-ALKYLPENT-4-ENOIC ACIDS AND THEIR ESTER DERIVATIVES
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Page/Page column 25, (2008/06/13)
A process for the preparation of optically active (4E)-5-halo-2-alkylpent-4-enoic acids and their ester derivatives by a stereoselective synthesis which employs camphorsultam as chiral auxiliary is disclosed; in particular methyl (2S, 4E)-5-chloro-2-isopropylpent-4-enoate is prepared, which is a key intermediate in the manufacturing of the new anti-hypertension drug Aliskiren. Furthermore novel N-(5-halo-2-alkylpent-4-enoyl) camphorsultams are provided. A process for the hydrolysis of substituted N-acylcamphorsultams with strong acids is also provided.
A practical large-scale synthesis of (3R,4R)-4-(Hydroxymethyl)pyrrolidin-3- ol via asymmetric 1,3-dipolar cycloaddition
Kotian, Pravin L.,Lin, Tsu-Hsing,El-Kattan, Yahya,Chand, Pooran
, p. 193 - 197 (2012/12/24)
(3R,4R)-4-(Hydroxymethyl)pyrrolidin-3-ol (1), which is a useful intermediate for the synthesis of various bioactive molecules, has been synthesized in 51% overall yield by 1,3-dipolar cycloaddition reaction from the dipolarophile, (E)-3-benzyloxypropenoyl-(2′S)-bornane-10,2-sultam (5), and the achiral ylide precursor, N-(benzyl)-N-(methoxymethyl)-N- (trimethylsilylmethyl)amine (6), without using chromatography and the subsequent reduction with LAH and catalytic hydrogenation. The diastereomers 7 and 8 were separated by crystallization, and efficient procedures were developed for the subsequent reactions to afford 1.
1,3-oxathiolan-5-ones useful in the production of antiviral nucleoside analogues
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, (2008/06/13)
A compound of the formula A, wherein R* is a chiral auxiliary, and where the configuration at the asymmetric carbon atom between oxygen and sulfur is (R), (S), or combinations of (R) and (S), useful in the preparation of enantiomerically enriched 1,3-oxathiolane nucleoside analogues, for example (?)-FTC and 3TC.
Progress toward the total synthesis of callipeltin A (I): Asymmetric synthesis of (3S,4R)-3,4-dimethylglutamine
Liang, Bo,Carroll, Patrick J.,Joullie, Madeleine M.
, p. 4157 - 4160 (2007/10/03)
(equation presented) During the total synthesis of the novel cyclic depsipeptide callipeltin A (1), the unit (3S,4R)-3,4-dimethylglutamine, was successfully synthesized by asymmetric Michael addition and subsequent electrophilic azidation. The key feature of this approach is the generation of three adjacent stereogenic centers using the same camphorsultam chiral auxiliary.
Chiral Polysiloxane-Fixed Metal 1,3-Diketonates (Chirasil-Metals) as Catalytic Lewis Acids for a Hetero Diels-Alder Reaction -Inversion of Enantioselectivity upon Catalyst-Polymer Binding
Keller, Fritz,Weinmann, Hilmar,Schurig, Volker
, p. 879 - 885 (2007/10/03)
A dimethylpolysiloxane chain is covalently bound to the monomeric Lewis acid catalyst (lR)-(+)-oxovanadium(IV) bis[3heptafluorobutanoylcamphorate] [(+)-5a] at the C-10 position of the camphor moiety yielding the novel chiral polymeric (1S)-(+)-oxovanadium(IV) bis[3-heptafluorobutanoylcamphoratej-dimethylpolysiloxane [(+)-6a][1]. The Lewis acid promoted hetero Diels-Alder reaction of //ans-l-methoxy-3(trimethylsilyloxy)-l,3-butadiene (1) and benzaldehyde (2) is studied in the presence of the enantiomerically pure monomeric (5a, 5b) and polymeric (6a, 6b) catalysts. The monomeric and polymeric catalysts of identical chirality'1' invoke opposite enantioselectivities toward the formation of 2-phenyl2,3-dihydro-4H-pyrone (4). This remarkable result is corroborated by numerous control experiments. Thus, it is demonstrated that the environment of the active site of the catalyst is changed when the complex is fixed to a polymeric chain. In contrast to 5 and 6, the monomeric 12 and polymeric 13 europium(HI) tris[3-heptafluorobutanoylcamphorates] of identical chirality invoke the same enantioselectivity toward the formation of 4. The concept of polymer attachment is utilized to recover the catalyst from the reaction mixture by precipitation and to recycle it for subsequent catalytic runs. VCH Verlagsgcscllschaft mbH,.
IRIDOIDS : ENANTIOSELECTIVE SYNTHESIS OF LOGANIN VIA AN ASYMMETRIC DIELS-ALDER REACTION
Vandewalle, M.,Van der Eycken, J.,Oppolzer, W.,Vullioud, C.
, p. 4035 - 4044 (2007/10/02)
Starting from (-)-camphor-10-sulfonic acid (5) the crystalline sultam 9 was readily prepared.TiCl4-mediated Diels-Alder addition of the N-crotonyl sultam 11 to cyclopentadiene, crystallization of the resulrting adduct 12 and subsequent reduction gave virtually pure (1S, 4R,5R, 6S)-1 together with recovered auxiliary 9.The loganin precursor 1 was transformed into norbonanone 20, which upon Baeyer-Villiger oxidation led to the suitably substituted cyclopentane 22 from which 1-B-O-methyl loganin aglucone (2) was readily available.
