- Copper-Catalyzed Cross-Nucleophile Coupling of β-Allenyl Silanes with Tertiary C-H Bonds: A Radical Approach to Branched 1,3-Dienes
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Described herein is a distinctive approach to branched 1,3-dienes through oxidative coupling of two nucleophilic substrates, β-allenyl silanes, and hydrocarbons appending latent functionality by copper catalysis. Notably, C(sp3)-H dienylation proceeded in a regiospecific manner, even in the presence of competitive C-H bonds that are capable of occurring hydrogen atom transfer process, such as those located at benzylic and other tertiary sites, or adjacent to an oxygen atom. Control experiments support the intermediacy of functionalized alkyl radicals.
- Shan, Qi-Chao,Hu, Lu-Min,Qin, Wei,Hu, Xu-Hong
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supporting information
p. 6041 - 6045
(2021/08/03)
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- One-pot synthesis of 3-substituted-4H-[1,2,3] triazolo[5,1-c][1,4]oxazin-6(7H)-ones from propargyl alcohols, chloroacetyl chloride, and sodium azide
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An efficient, one-pot synthesis of 3-substituted-4H-[1,2,3]triazolo[5,1-c][1,4]oxazin-6(7H)-ones is developed via sequential esterification, substitution, and 1,3-dipolar cycloaddition processes of various propargyl alcohols, chloroacetyl chloride, and so
- Chen, Jun-Min,Liu, Xiao-Ling,Sheng, Shou-Ri,Wei, Mei-Hong,Zhang, Xiao-Lan
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p. 482 - 485
(2020/11/30)
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- When Gold Meets Perfumes: Synthesis of Olfactive Compounds via Gold-Catalyzed Cycloisomerization Reactions
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An efficient, and mild synthetic route for the preparation of functionalized volatile oxa-bicyclo[4.1.0]-hept-4-ene (29 compounds, 44-98% isolated yields) has been developed relying on the association of IPrAuCl with NaBArF. The remarkable selectivity was demonstrated on a 1 g and 25 g scale with low catalyst loadings. The synthetic utility of these low-molecular-weight enols was further demonstrated by the derivatization of some adducts and by the unprecedented olfactory evaluation of all bicyclic derivatives.
- Laher, Romain,Marin, Christophe,Michelet, Véronique
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supporting information
p. 4058 - 4062
(2020/04/20)
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- Copper-Catalyzed Propargylation of Nitroalkanes
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Using a commercially available, inexpensive, and abundant copper catalyst system, an efficient α-functionalization of nitroalkanes with propargyl bromides is now established. This mild and robust method is highly functional group tolerant and provides straightforward access to complex secondary and tertiary homopropargylic nitroalkanes. Moreover, the utility of these α-propargylated nitroalkanes is demonstrated through downstream functionalization to biologically relevant, five-membered N-heterocycles such as pyrroles and 2-pyrrolines.
- Kim, Raphael S.,Dinh-Nguyen, Linh V.,Shimkin, Kirk W.,Watson, Donald A.
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supporting information
p. 8106 - 8110
(2020/11/02)
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- Photocatalyzed Diastereoselective Isomerization of Cinnamyl Chlorides to Cyclopropanes
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Endergonic isomerizations are thermodynamically unfavored processes that are difficult to realize under thermal conditions. We report a photocatalytic and diastereoselective isomerization of acyclic cinnamyl chlorides to strained cyclopropanes. Quantum mechanical calculations (uM06-2X and DLPNO), including TD-DFT calculations, and experimental studies provide evidence for the energy transfer from an iridium photocatalyst to the allylic chloride substrate followed by C-Cl homolytic cleavage. Subsequent Cla￠ radical migration forms a localized triplet 1,3-diradical intermediate that, after intersystem crossing, undergoes ring-closing to form the desired product. The mild reaction conditions are compatible with a broad range of functional groups to generate chlorocyclopropanes in high yields and diastereoselectivities. A more efficient process is developed by addition of a catalytic amount of a nickel complex, and we propose a novel role for this cocatalyst to recycle an allyl chloride byproduct generated in the course of the reaction. The reaction is also shown to be stereoconvergent, as an E/Z mixture of cinnamyl chlorides furnish the anti-chlorocyclopropane product in high diastereoselectivity. We anticipate that the use of a visible light activated photocatalyst to transform substrates in combination with a transition metal catalyst to recycle byproducts back into the catalytic cycle will provide unique opportunities for the discovery of new reactivity.
- Dykstra, Ryan,Gutierrez, Osvaldo,Martin, Robert T.,Tambar, Uttam K.,Troian-Gautier, Ludovic,Xu, Bin
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supporting information
p. 6206 - 6215
(2020/04/27)
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- Applications of Thermal Activation, Ball-milling and Aqueous Medium in Stereoselective Michael Addition of Nitromethane to Enynones Catalyzed by Chiral Squaramides
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Stereoselective addition of nitromethane to conjugated en-ynones was performed through the application of chiral squaramides. Three non-classical approaches to promote the addition reaction were tested, including activation of the nucleophile by inorganic base in a biphasic aqueous system, thermal activation, and ball-milling. Hydrogen-bonding catalysis was effective in all these methods, providing 1,4-addition products in high yields and stereoselectivities of up to 98% requiring 1–5 mol% of Cinchona alkaloid squaramide. (Figure presented.).
- Ignatiuk, ?aneta A.,Janicki, Miko?aj J.,Góra, Robert W.,Konieczny, Krzysztof,Kowalczyk, Rafa?
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supporting information
p. 1108 - 1116
(2019/01/30)
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- Catalytic asymmetric synthesis of 2,5-dihydrofurans using synergistic bifunctional Ag catalysis
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We report a bifunctional Ag catalyst promoted intramolecular capture of oxonium ylides with alkynes for the enantioselective synthesis of 2,5-dihydrofurans. This represents unprecedented synergistic catalysis of a bifunctional Ag catalyst. Mechanistic studies revealed that [(R)-3,5-DM-BINAP](AgSbF6)2 (9) is likely to be the active catalytic species and that the reaction involves second order kinetics with respect to 9, suggesting that two molecules of 9 are involved in the intramolecular trapping of a Ag-associated oxonium ylide with a Ag-activated alkyne. Based on our mechanistic hypothesis, we further optimized the reaction, rendering a facile approach to 2,5-dihydrofurans in good to excellent yields in a highly chemo- and enantioselective fashion.
- Shi, Taoda,Teng, Shenghan,Gopi Krishna Reddy, Alavala,Guo, Xin,Zhang, Yueteng,Moore, Kohlson T.,Buckley, Thomas,Mason, Damian J.,Wang, Wei,Chapman, Eli,Hu, Wenhao
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supporting information
p. 8737 - 8744
(2019/10/16)
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- Sodium Phenoxide Mediated Hydroxymethylation of Alkynylsilanes with N-[(Trimethylsiloxy)methyl]phthalimide
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The hydroxymethylation of alkynylsilanes with formaldehyde generated in situ from N-[(trimethylsiloxy)methyl]phthalimide proceeds in the presence of a stoichiometric amount of NaOPh. The reaction occurs at room temperature by using an operationally simple one-step procedure. A variety of alkynylsilanes possessing electron-donating, electron-withdrawing, and halogen groups (including heteroaryl-substituted alkynylsilanes) provide hydroxymethylated products.
- Asano, Narumi,Sasaki, Keita,Chataigner, Isabelle,Shigeno, Masanori,Kondo, Yoshinori
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supporting information
p. 6926 - 6930
(2017/12/26)
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- Pd(ii)-catalyzed formal [4+1] cycloaddition reactions of diazoacetates and aryl propargyl alcohols to form 2,5-dihydrofurans
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A Pd(ii)-catalyzed formal [4+1] cycloaddition of aryl diazoacetates and aryl propargyl alcohols is reported to afford 2,5-dihydrofuran derivatives as the dominant product over other traditional ones. The auto-tandem catalytic process is proposed to occur via Pd(ii)-catalyzed intermolecular oxonium ylide formation and subsequent intramolecular trapping of the ylide with Pd(ii)-activated alkynes.
- Shi, Taoda,Guo, Xin,Teng, Shenghan,Hu, Wenhao
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supporting information
p. 15204 - 15207
(2015/10/12)
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- AMINE COMPOUND AND PHARMACEUTICAL USE THEREOF
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Provided is a novel amine compound represented by the following formula (I) having a superior peripheral blood lymphocyte decreasing action and superior in the immunosuppressive action, rejection suppressive action and the like, which shows decreased side effects of, for example, bradycardia and the like, or a pharmaceutically acceptable acid addition salt thereof, or a hydrate thereof, or a solvate thereof. wherein each symbol is as defined in the specification.
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Page/Page column 92
(2010/04/25)
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- Synthesis of 3-substituted furans by hydroformylation
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A simple and novel method for the synthesis of 3-substituted furans by the hydroformylation of substituted propargylic alcohols is described using rhodium acetate and triphenylphosphine in dichloromethane. The hydroformylation reaction proceeds in a regio
- Nanayakkara, Peru,Alper, Howard
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p. 545 - 550
(2007/10/03)
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- ALYKYLENE DERIVATIVE HAVING EDG RECEPTOR ANTAGONISM
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PROBLEM TO BE SOLVED: To provide novel compounds having EDG (endothelial differentiation gene) receptor antagonism which are useful as active components of drugs for preventing and/or treating inflammatory diseases or the like. SOLUTION: The compounds are represented by formula (I) (wherein R1 is hydrogen or an alkyl group; R2 is hydrogen present at any substitutable position on ring C or a substituent such as a hydroxy group, a carboxy group, and a nitro group; R3 is hydrogen present at any substitutable position on ring D or a substitutent such as a hydroxy group and an aralkyloxy group; X is an alkylamino group, an amino group or the like; Y is a carboxy group, a sulfo group or a phosphono group; Z is oxygen, sulfur or the like; a ring represented by A is a 5- or 6-membered saturated or unsaturated hydrocarbon ring; and a ring represented by B is a 4- or 7-membered saturated or unsaturated hydrocarbon ring containing one -C=C- as a partial structure shown in the above formula) and include their salts and their esters.
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Page/Page column 100
(2010/02/12)
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