- A Unified and Desymmetric Approach to Chiral Tertiary Alkyl Halides
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Enantioenriched tertiary alkyl halides are prevalent in bioactive molecules and can serve as versatile synthetic intermediates to construct complex structures. While conventional access to these motifs often hinges on stereoselective carbon-halogen or carbon-carbon bond formation reactions, desymmetric approaches using halogenated and prochiral tetrasubstituted carbons are largely elusive in comparison. Here, we report that a suite of dinuclear zinc catalysts with a prolinol- or pipecolinol-derived tetradentate ligand can reductively desymmetrize a large collection of easily available halomalonic esters to α-halo-β-hydroxyesters. These polyfunctionalized tertiary alkyl fluorides, chlorides, and bromides proved to be useful intermediates toward fluorinated drug analogs and polyhalogenated monoterpenes. The facile intramolecular epoxidation of the chiral chloride and bromide products has also enabled expeditious access to natural products containing tertiary alcohol motifs.
- Huang, Zhongxing,Low, Kam-Hung,Zhang, Suihan,Zheng, Yin,Zi, Weiwei
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supporting information
p. 1951 - 1961
(2022/02/09)
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- Synthesis of Cyclopentenones through Rhodium-Catalyzed C-H Annulation of Acrylic Acids with Formaldehyde and Malonates
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An efficient rhodium-catalyzed protocol for the synthesis of cyclopentenones based on a three-component reaction of acrylic acids, formaldehyde, and malonates via vinylic C-H activation is reported. Exploratory studies showed that 5-alkylation of as-prepared cyclopentenones could be realized smoothly by the treatment of a variety of alkyl halides with a Na2CO3/MeOH solution. Excess formaldehyde and malonate led to a multicomponent reaction that afforded the multisubstituted cyclopentenones through a Michael addition.
- Yu, Shuling,Hong, Chao,Liu, Zhanxiang,Zhang, Yuhong
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supporting information
p. 5054 - 5059
(2021/07/20)
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- Electrochemistry-Enabled Ir-Catalyzed Vinylic C-H Functionalization
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Synergistic use of electrochemistry and organometallic catalysis has emerged as a powerful tool for site-selective C-H functionalization, yet this type of transformation has thus far mainly been limited to arene C-H functionalization. Herein, we report the development of electrochemical vinylic C-H functionalization of acrylic acids with alkynes. In this reaction an iridium catalyst enables C-H/O-H functionalization for alkyne annulation, affording α-pyrones with good to excellent yields in an undivided cell. Preliminary mechanistic studies show that anodic oxidation is crucial for releasing the product and regeneration of an Ir(III) intermediate from a diene-Ir(I) complex, which is a coordinatively saturated, 18-electron complex. Importantly, common chemical oxidants such as Ag(I) or Cu(II) did not give significant amounts of the desired product in the absence of electrical current under otherwise identical conditions.
- Yang, Qi-Liang,Xing, Yi-Kang,Wang, Xiang-Yang,Ma, Hong-Xing,Weng, Xin-Jun,Yang, Xiang,Guo, Hai-Ming,Mei, Tian-Sheng
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supporting information
p. 18970 - 18976
(2019/12/04)
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- Chiral compound, liquid crystal composition containing the chiral compound, optically anisotropic body, and liquid crystal display device
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The invention discloses a chiral compound, a liquid crystal composition containing the chiral compound, an optical anisotropic body and a liquid crystal display device. The structural formula of the chiral compound is shown as the following formula I, and
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Paragraph 0061; 0065-0069
(2019/12/02)
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- Computational and experimental studies on copper-mediated selective cascade C-H/N-H annulation of electron-deficient acrylamide with arynes
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An efficient and convenient copper-mediated method has been developed to achieve direct cascade C-H/N-H annulation to synthesize 2-quinolinones from electron-deficient acrylamides and arynes. This method highlights an emerging but simple strategy to transform inert C-H bonds into versatile functional groups in organic synthesis to provide a new method of synthesizing 2-quinolinones efficiently. Mechanistic investigations by experimental and density functional theory (DFT) studies suggest that an organometallic C-H activation via a Cu(iii) intermediate is likely to be involved in the reaction.
- Chen, Chao,Hao, Yu,Zhang, Ting-Yu,Pan, Jin-Long,Ding, Jun,Xiang, Heng-Ye,Wang, Man,Ding, Tong-Mei,Duan, Abing,Zhang, Shu-Yu
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supporting information
p. 755 - 758
(2019/01/21)
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- Bifunctional Iminophosphorane Catalyzed Enantioselective Sulfa-Michael Addition to Unactivated α-Substituted Acrylate Esters
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The highly enantioselective sulfa-Michael addition of alkyl thiols to unactivated α-substituted acrylate esters catalyzed by a bifunctional iminophosphorane organocatalyst under mild conditions is described. The strong Br?nsted basicity of the iminophosphorane moiety of the catalyst provides the necessary activation of the alkyl thiol pro-nucleophile, while the two tert-leucine residues flanking a central thiourea hydrogen-bond donor facilitate high enantiofacial selectivity in the protonation of the transient enolate intermediate. The reaction is broad in scope with respect to the alkyl thiol, the ester moiety, and the α-substituent of the α,β-unsaturated ester, affords sulfa-Michael adducts in excellent yields (up to >99%) and enantioselectivities (up to 96% ee), and is amenable to decagram scale-up using catalyst loadings as low as 0.05 mol %.
- Farley, Alistair J. M.,Sandford, Christopher,Dixon, Darren J.
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supporting information
p. 15992 - 15995
(2016/01/15)
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- Protected amino hydroxy adamantane carboxylic acid and process for its preparation
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Dipeptidyl peptidase IV (DP 4) inhibiting compounds are provided. The provided compounds can be used for treating diabetes and related diseases, especially Type II diabetes, and other diseases as set out herein, employing such DP 4 inhibitor or a combination of such DP 4 inhibitor and one or more of another antidiabetic agent such as metformin, glyburide, troglitazone, pioglitazone, rosiglitazone and/or insulin and/or one or more of a hypolipidemic agent and/or anti-obesity agent and/or other therapeutic agent.
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Paragraph 0430; 0431
(2015/11/24)
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- Pyrimidine Non-Classical Cannabinoid Compounds and Related Methods of Use
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Disclosed are compounds of the formula I: wherein R1, R2, V, W, X, Y and Z can be as defined herein. The compounds can be used in the treatment of disorders mediated by the cannabinoid receptors.
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Page/Page column 9
(2009/12/05)
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- Pyridine Non-Classical Cannabinoid Compounds and Related Methods of Use
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wherein R1, R2, V, W, X, Y and Z can be as defined herein. The compounds can be used in the treatment of disorders mediated by the cannabinoid receptors.
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Page/Page column 7
(2009/12/05)
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- N-SULFONYLPIPERIDINES AS METALLOPROTEINASE INHIBITORS (TACE)
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Compounds of formula (1), wherein Z is -CONR15OH or -N(OH)CHO and X is -(CR9R10)t-Q-(CR11R12)u- (where t and u are independently 0 or 1 with the proviso that t and u cannot both be 0);are inhibitors o
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Page/Page column 75
(2010/02/06)
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- SULPHONYLPIPERIDINE DERIVATIVES CONTAINING AN ARYL OR HETEROARYL GROUP FOR USE AS MATRIX METALLOPROTEINASE INHIBITORS
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A compound of formula (1), wherein B is an ortho substituted monocyclic aryl or heteroaryl group or a bicyclic aryl or heteroaryl group; useful in the inhibition of one or more metalloproteinases, and in particular TACE.
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Page/Page column 64; 65
(2010/02/06)
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- Alkylation of malonic and acetoacetic esters in an ionic liquid
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1-Butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) has been used as a recyclable medium in the alkylation of malonic and acetoacetic esters with alkyl, benzyl and prenyl halides.
- Kryshtal, Galina V.,Zhdankina, Galina M.,Zlotin, Sergei G.
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- Nitration of α,β-unsaturated esters. Evidence for positive charge build-up adjacent to carbonyl carbon
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Reactive intermediates formed in the nitration of certain α,β-unsaturated esters with nitronium tetrafluoroborate exhibit behaviour expected of highly reactive α-carbonyl cations. Three diagnostic reaction types have been observed which indicate the presence of these destabilised cations: (i) trapping in a Ritter reaction, (ii) cyclopropane formation from propyl cations, (iii) Wagner-Meerwein migration of alkyl groups. Semi-empirical calculations of the relative gas-phase stabilities of the proposed intermediate cations are useful in rationalising the observed chemistry.
- Hewlins, Stuart A.,Murphy, John A.,Lin, Jian,Hibbs, David E.,Hursthouse, Michael B.
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p. 1559 - 1570
(2007/10/03)
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- Barbiturate assay, tracers, immunogens, antibodies and kit
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The present invention is directed to a fluorescence polarization immunoassay for barbiturates, to the various components needed for preparing and carrying out such an assay, and to methods of making these components. Specifically, tracers, immunogens and antibodies are disclosed, as well as methods for preparing them and a reagent kit containing them. The tracers and the immunogens are made from substituted barbiturate compounds. A fluorescein moiety is included in the tracer, while a poly(amino acid) forms a part of the immunogen. The assay is conducted by measuring the degree of polarization retention of plane-polarized light that has been passed through a sample containing antiserum and tracer.
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- LONG-ACTING CONTRACEPTIVE AGENTS: CYCLOPROPYL AND CYCLOBUTYL ESTERS OF NORETHISTERONE
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Several esters of norethisterone (17α-ethynyl-17β-hydroxyestr-4-en-3-one) with carboxylic acids containing a cyclopropyl or cyclobutyl ring have been synthesized and the stereochemistries of the side-chains determined.
- Shafiee, A.,Vossoghi, M.,Savabi, F.,Vlahov, R.,Tarpanov, V.,et al.
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p. 291 - 308
(2007/10/02)
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