2328-26-9Relevant academic research and scientific papers
Iron-catalysed enantioselective Suzuki-Miyaura coupling of racemic alkyl bromides
Iwamoto, Takahiro,Okuzono, Chiemi,Adak, Laksmikanta,Jin, Masayoshi,Nakamura, Masaharu
, p. 1128 - 1131 (2019)
The first iron-catalysed enantioselective Suzuki-Miyaura coupling reaction has been developed. In the presence of catalytic amounts of FeCl2 and (R,R)-QuinoxP?, lithium arylborates are cross-coupled with tert-butyl α-bromopropionate in an enantioconvergent manner, enabling facile access to various optically active α-arylpropionic acids including several nonsteroidal anti-inflammatory drugs (NSAIDs) of commercial importance. (R,R)-QuinoxP? is specifically able to induce chirality when compared to analogous P-chiral ligands that give racemic products, highlighting the critical importance of transmetalation in the present asymmetric cross-coupling system.
Catalytic enantioselective protonation of lithium ester enolates generated by conjugate addition of arylthiolate to enoates
Nishimura, Katsumi,Ono, Masashi,Nagaoka, Yasuo,Tomioka, Kiyoshi
, p. 440 - 442 (2001)
A chiral ligand, a catalytic amount of lithium cation, and no chiral proton source: These are features of the present asymmetric addition-protonation of propenoates with 2-trimethylsilylbenzenethiol. The reaction is catalyzed by a combination of lithium 2-trimethylsilylbenzenethiolate and the chiral ligand 1. Desulfurization of the product affords 2-substituted propanoates with high ee values and without racemization. Furthermore, 1 can be recovered quantitatively for reuse.
Enantioselective α-Arylation of Ketones via a Novel Cu(I)-Bis(phosphine) Dioxide Catalytic System
Escudero-Casao, Margarita,Licini, Giulia,Orlandi, Manuel
supporting information, p. 3289 - 3294 (2021/04/07)
A novel catalytic system based on copper(I) and chiral bis(phosphine) dioxides is described. This allows the arylation of silyl enol ethers to access enolizable α-arylated ketones in good yields and enantiomeric excess up to 95%. Noncyclic ketones are amenable substrates with this method, which complements other approaches based on palladium catalysis. Optimization of the ligand structure is accomplished via rational design driven by correlation analysis. Preliminary mechanistic hypotheses are also evaluated in order to identify the role of chiral bis(phosphine) dioxides.
Synthetic method of chiral 2-aryl propionate
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Paragraph 0039-0046, (2020/04/02)
The invention belongs to the technical field of chemical synthesis, and relates to a synthetic method of chiral 2-aryl propionate, in particular to enantioselective synthesis of 2-aryl propionate. Thesynthetic method comprises the following steps: adding a copper salt, a chiral phosphine ligand, a silicon-hydrogen compound (in terms of SiH), ROH and 2-aryl acrylate in a certain ratio into a reaction bottle, carrying out a reaction in a reaction solvent at -50 to 40 DEG C for 0.25-6 h, and successively performing hydrolyzing, liquid separating, extracting, washing, drying and column chromatography after the reaction is finished, thereby obtaining the target compound 2-aryl propionate. Compared with the prior art, the method has the advantages that the 2-aryl acrylate is reduced by adopting a Cu catalytic system, a catalyst, namely a Cu compound is low in price, and the limitation of hydrogen high-pressure reduction and a noble metal catalyst is broken through. Chiral 2-aryl propionic acid can be obtained through a simple hydrolysis reaction of 2-aryl propionate, and a part of the compounds of 2-aryl propionate are effective components of current commercially-available drugs suchas ibuprofen and naproxen.
Nickel/Photoredox-Catalyzed Asymmetric Reductive Cross-Coupling of Racemic α-Chloro Esters with Aryl Iodides
Guan, Haixing,Mao, Jianyou,Walsh, Patrick J.,Zhang, Qianwen
supporting information, p. 5172 - 5177 (2020/02/20)
A unique nickel/organic photoredox co-catalyzed asymmetric reductive cross-coupling between α-chloro esters and aryl iodides is developed. This cross-electrophile coupling reaction employs an organic reductant (Hantzsch ester), whereas most reductive cross-coupling reactions use stoichiometric metals. A diverse array of valuable α-aryl esters is formed under these conditions with high enantioselectivities (up to 94 %) and good yields (up to 88 %). α-Aryl esters represent an important family of nonsteroidal anti-inflammatory drugs. This novel synergistic strategy expands the scope of Ni-catalyzed reductive asymmetric cross-coupling reactions.
Synthesis method of (S)-2-aryl propionate compound
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Paragraph 0096-0099; 0120-0123, (2020/08/09)
The invention discloses a synthesis method of a (S)-2-aryl propionate compound. The (S)-2-aryl propionate compound shown in the formula IV is obtained by taking a compound shown in a formula I and a compound shown in a formula II as raw materials and reacting under the conditions of a chiral ligand shown in a formula III, a nickel catalyst, a photocatalyst, a reducing agent and alkali under the condition of visible light. The method has the advantages of cheap and easily available raw materials, convenient generation, mild conditions, environmental protection and safety, the photocatalyst canbe recycled, the production cost is greatly reduced, the test operation is simple, less waste is generated, and the method can be developed into an industrial production method.
Cobalt-Catalyzed Enantioselective Negishi Cross-Coupling of Racemic α-Bromo Esters with Arylzincs
Liu, Feipeng,Zhong, Jiangchun,Zhou, Yun,Gao, Zidong,Walsh, Patrick J.,Wang, Xueyang,Ma, Sijie,Hou, Shicong,Liu, Shangzhong,Wang, Minan,Wang, Min,Bian, Qinghua
supporting information, p. 2059 - 2064 (2018/02/14)
The first cobalt-catalyzed enantioselective Negishi cross-coupling reaction, and the first arylation of α-halo esters with arylzinc halides, are disclosed. Employing a cobalt-bisoxazoline catalyst, various α-arylalkanoic esters were synthesized in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield). A diverse range of functional groups, including ether, halide, thioether, silyl, amine, ester, acetal, amide, olefin and heteroaromatics is tolerated by this method. This method was suitable for gram-scale reactions, enabling the synthesis of (R)-xanthorrhizol with high enantiopurity. Radical clock experiments support the intermediacy of radicals.
Ni-Catalyzed chemoselective alcoholysis of: N -acyloxazolidinones
Huang, Pei-Qiang,Geng, Hui
supporting information, p. 593 - 599 (2018/02/14)
Although N-acyloxazolidinone-based (catalytic) asymmetric synthetic methodologies occupy an important position in modern organic synthesis, the catalytic cleavage of a chiral auxiliary remains underdeveloped. We report the Ni(cod)2/bipyr.-catalyzed alcoholysis of N-acyloxazolidinones to deliver esters. The reaction is broad in scope for both N-acyloxazolidinone substrates and alcohol nucleophiles, and displays good functional group tolerance and excellent chemoselectivity. A gram-scale methanolysis allowed the enantioselective synthesis of the C22-C26 segment of a close analogue of the potent immunosuppressant agent FK506.
Structural insights into the ene-reductase synthesis of profens
Waller,Toogood,Karuppiah,Rattray,Mansell,Leys,Gardiner,Fryszkowska,Ahmed,Bandichhor,Reddy,Scrutton
, p. 4440 - 4448 (2017/07/10)
Reduction of double bonds of α,β-unsaturated carboxylic acids and esters by ene-reductases remains challenging and it typically requires activation by a second electron-withdrawing moiety, such as a halide or second carboxylate group. We showed that profen precursors, 2-arylpropenoic acids and their esters, were efficiently reduced by Old Yellow Enzymes (OYEs). The XenA and GYE enzymes showed activity towards acids, while a wider range of enzymes were active towards the equivalent methyl esters. Comparative co-crystal structural analysis of profen-bound OYEs highlighted key interactions important in determining substrate binding in a catalytically active conformation. The general utility of ene reductases for the synthesis of (R)-profens was established and this work will now drive future mutagenesis studies to screen for the production of pharmaceutically-active (S)-profens.
Enantioselective Hydrogen Atom Transfer: Discovery of Catalytic Promiscuity in Flavin-Dependent 'Ene'-Reductases
Sandoval, Braddock A.,Meichan, Andrew J.,Hyster, Todd K.
, p. 11313 - 11316 (2017/08/30)
Flavin has long been known to function as a single electron reductant in biological settings, but this reactivity has rarely been observed with flavoproteins used in organic synthesis. Here we describe the discovery of an enantioselective radical dehalogenation pathway for α-bromoesters using flavin-dependent 'ene'-reductases. Mechanistic experiments support the role of flavin hydroquinone as a single electron reductant, flavin semiquinone as the hydrogen atom source, and the enzyme as the source of chirality.
