- Radical Carbonyl Umpolung Arylation via Dual Nickel Catalysis
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The formation of carbon-carbon bonds lies at the heart of synthetic organic chemistry and is widely applied to construct complex drugs, polymers, and materials. Despite its importance, catalytic carbonyl arylation remains comparatively underdeveloped, due
- Huang, Huan-Ming,Bellotti, Peter,Erchinger, Johannes E.,Paulisch, Tiffany O.,Glorius, Frank
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supporting information
p. 1899 - 1909
(2022/02/01)
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- Consecutive borylcupration/C-C coupling of ?-alkenyl aldehydes towards diastereoselective 2-(borylmethyl)cycloalkanols
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Copper(i) catalyzes the borylative cyclization of ?-alkenyl aldehydes through chemo- and regioselective addition of Cu-B to C?C and concomitant intramolecular 1,2-addition of Cu-C on C?O. The products are formed in an exclusive diastereoselective manner and computational analysis identifies the key points for the observed chemo- and diastereoselectivity.
- Carbó, Jorge J.,Fernández, Elena,Maza, Ricardo J.,Royes, Jordi
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supporting information
p. 5973 - 5976
(2020/06/05)
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- Cyclization Reactions of Oxyallyl Cation. A Method for Cyclopentane Ring Formation
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Unsaturated oxyallyl cations with a suitably positioned alkene bond undergo 5-exo-cyclization with the formation of vinylcyclopentane derivatives. Alkyne analogues provide allenes. The reaction proceeds with a moderate to excellent level of stereoselectiv
- Vulovic, Bojan,Trmcic, Milena,Matovic, Radomir,Saicic, Radomir N.
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p. 9618 - 9621
(2019/12/24)
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- Nickel-Catalyzed α-Allylation of Aldehydes and Tandem Aldol Condensation/Allylation Reaction with Allylic Alcohols
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An additive-free nickel-catalyzed α-allylation of aldehydes with allyl alcohol is reported. The reaction is promoted by 1 mol % of in situ formed nickel complex in methanol, and water is the sole by-product of the reaction. The experimental conditions allow the conversion of various α-branched aldehydes and α,β-unsaturated aldehydes as nucleophiles. The same catalyst and reaction conditions enabled a tandem aldol condensation of aldehyde/α-allylation reaction.
- Bernhard, Yann,Thomson, Brodie,Ferey, Vincent,Sauthier, Mathieu
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supporting information
p. 7460 - 7464
(2017/06/13)
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- Gold(i)-catalyzed dehydrogenative cycloisomerization of 1,5-enynes
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The gold(i)-catalyzed dehydrogenative cycloisomerization of cyclopropane-tethered 1,5-enynes proceeded smoothly to give multisubstituted benzene derivatives in good to excellent yields. Synthetically important benzocyclobutenes can be produced in high yields in the presence of a gold(i) catalyst and DDQ. Furthermore, this reaction also works very well for non-cyclopropane tethered 1,5-enynes.
- Chen, Gen-Qiang,Fang, Wei,Wei, Yin,Tang, Xiang-Ying,Shi, Min
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p. 10799 - 10802
(2016/09/07)
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- PROCESS FOR PREPARING GABAPENTIN
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A process for preparing gabapentin of formula 1, which comprises Formula (I) converting 1-allyl-cyclohexanecarboxaldehyde into 1-allyl-cyclohexanecarbonitrile; ozonizing 1-allyl-cyclohexanecarbonitrile to obtain 1-cyano-cyclohexaneacetaldehyde; acetalizing 1-cyano-cyclohexaneacetaldehyde with a suitable acetalizing agent to give the corresponding acetal and converting the latter into gabapentin.
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Page/Page column 11-12
(2008/06/13)
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- Reduction of 5-(bromomethyl)-1-pyrrolinium bromides to 2-(bromomethyl)pyrrolidines and their transformation into piperidin-3-ones through an unprecedented ring expansion-oxidation protocol
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3,3-Dialkyl-5-(bromomethyl)-1-pyrrolinium bromides, prepared via bromocyclization of N-(2,2-dialkyl-4-pentenylidene)amines by means of bromine in dichloromethane, were reduced to 4,4-dialkyl-2-(bromomethyl)pyrrolidines for the first time using borane dimethyl sulfide in dichloromethane. Furthermore, the latter 2-(bromomethyl)pyrrolidines were transformed into the corresponding piperidin-3-ones through an unprecedented ring expansion-oxidation protocol in dimethylsulfoxide in the presence of potassium carbonate. Reduction of 5,5-dialkylpiperidin-3-ones by means of sodium borohydride in methanol afforded 5,5-dialkyl-3-hydroxypiperidines in good yields.
- D'hooghe, Matthias,Baele, Jan,Contreras, Jan,Boelens, Mark,Kimpe, Norbert De
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scheme or table
p. 6039 - 6042
(2009/04/11)
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- Direct catalytic intermolecular α-allylic alkylation of aldehydes by combination of transition-metal and organocatalysis
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(Chemical Equation Presented) All in the same pot together: The direct catalytic α-allylic alkylation of aldehydes and cyclic ketones is achieved by using a simple, unprecedented one-pot procedure. Transition-metal and enamine catalysis are combined so that α-allylic alkylated aldehydes and cyclic ketones are formed in high yield with a direct catalytic chemo- and regioselective method.
- Ibrahem, Ismail,Cordova, Armando
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p. 1952 - 1956
(2007/10/03)
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- NOVEL 4-(2FUROYL)AMINOPIPERIDINES, INTERMEDIATES IN SYNTHESIZING THE SAME,PROCESS FOR PRODUCING THE SAME AND MEDICINAL USE OF THE SAME
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There are provided novel 4-(2-furoyl)aminopiperidines represented by the general formula (I), their synthetic intermediates, processes for their preparation and medicaments containing them. In the above formula, X is CH or N, and Y is a group of the following general formula (II), formula (II-a) or formula (III): wherein a, b and c are each an integer of 0-6; Z is CH2 or NH; W is O or S; T is O or N-R15 wherein R15 is H, a C1-C6 alkyl group, a benzyl group or a phenethyl group; and R1 is H, a C1-C6 alkoxycarbonyl group, a benzyloxycarbonyl group, or the like.The 4-(2-furoyl) aminopiperidine derivatives according to this invention possess opioid μ antagonistic activity and are useful for the treatment or prevention of side effects which are caused by μ receptors agonist and which are selected from constipation, nausea/emesis or itch, or for the treatment or prevention of idiopathic constipation, postoperative ileus, paralytic ileus, irritable bowel syndrome or chronic pruritus.
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- Synthesis of 3-alkenylamines, 4-alkenylamines and 3-allenylamines via a transamination procedure
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3-Alkenylamines, 4-alkenylamines and 3-allenylamines were synthesized conveniently by potassium t-butoxide induced transamination of α-vinylaldimines, α-allylaldimines or α-allenylaldimines followed by hydrolysis with aqueous oxalic acid.
- De Kimpe, Norbert,De Smaele, Dirk,Hofkens, Arn,Dejaegher, Yves,Kesteleyn, Bart
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p. 10803 - 10816
(2007/10/03)
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- Neighboring Group Participation in Lewis Acid-Promoted and Annulations. The Stereocontrolled Synthesis of Tricyclic Ethers
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A variety of 1,4- and 1,5-keto aldehydes derived from cycloalkanes are coupled with the bis(trimethylsilyl) enol ether of methyl acetoacetate in the presence of either TMSOTf or TrSbCl6 to generate tricyclic ethers.The reactions proceed with excellent regiochemical control by a mechanism involving neighboring group participation.This mechanism involves initial formation of a bicyclic oxocarbenium ion intermediate from the keto aldehyde substrates.The geometries of selected bicyclic intermediates have been optimized using the AM1 method allowing successful prediction of the stereochemical outcomes in the cyclization in most cases.Epimerization of α-chiral keto aldehyde substrates does not appear to occur in these Lewis acid-promoted annulation reactions.
- Molander, Gary A.,Cameron, Kimberly O.
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p. 5931 - 5943
(2007/10/02)
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- CYCLISATION OF IMINE RADICALS DERIVED FROM SULPHENYLIMINES: A SIMPLE ACCESS TO Δ1-PYRROLINES
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Treatment of various sulphenylimines containing a γ,δ-double bond with tri-n-butylstannane affords the corresponding pyrroline derivatives in good yield.
- Boivin, Jean,Fouquet, Eric,Zard, Samir Z.
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- New Methods for the Syntheses of α,β-Unsaturated Ketones, Aldehydes, and Nitriles by the Palladium-Catalyzed Reactions of Allyl β-Oxo Esters, Allyl 1-Alkenyl Carbonates, and Allyl α-Cyano Esters
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Allyl β-oxo esters, allyl 1-alkenyl carbonates, and allyl α-cyano esters are converted into α,β-unsaturated ketones, aldehydes, and nitriles by palladium-catalyzed intramolecular decarboxylation-dehydrogenation.Palladium-phosphine complexes such as Pd(OAc)2-PPh3, Pd(OAc)2-dppe, or Pd2(dba)3*CHCl3-PPh3, are effective catalysts.Yields depend on solvents and on the mole ratio of palladium to phosphine.The optimum Pd/P ratio for each substrate was determined.Use of nitriles as solvents is essential for the dehydrogenation.
- Minami, Ichiro,Nisar, Mohammad,Yuhara, Masami,Shimizu, Isao,Tsuji, Jiro
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p. 992 - 998
(2007/10/02)
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- 2-Allylisourea as an Effective Agent for Direct α-Allylation of Ketone and Aldehyde Assisted by Palladium(0) under Neutral Conditions
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Direct α-allylation of a variety of ketones and aldehydes with 2-allylisourea took place in the presence of a catalytic amount of a palladium(0) complex under neutral and mild conditions.Scope and limitations of this novel method have been investigated.
- Inoue, Yoshio,Toyofuku, Masanori,Taguchi, Masaaki,Okada, Shin-ichi,Hashimoto, Harukichi
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p. 885 - 892
(2007/10/02)
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- MODIFIED AZA-CLAISEN REARRANGEMENT: GENERATION AND ISOMERIZATION OF ALLYL ENAMMONIUM SALTS
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Base-promoted reaction of ketones and diethyl (diazomethyl)phosphonate in the presence of allylic amines affords allylic enamines in good yields.These enamines undergo -sigmatropic rearrangement upon alkylation and heating at 80 deg C to iminium salts which can be hydrolyzed to aldehydes.The procedure allows generation of quaternary carbon centers under mild reaction conditions.
- Gilbert, John C.,Senaratne, K. P. A.
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p. 2303 - 2306
(2007/10/02)
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- PALLADIUM-CATALYZED ALLYLATION OF KETONES AND ALDEHYDES VIA ALLYL ENOL CARBONATES
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Rearrangement of allyl enol carbonates, prepared from ketones or aldehydes by trapping their enolates with allyl chloroformate, to give α-allyl ketones or aldehydes regioselectively is catalyzed by palladium-phosphine complexes under mild conditions.
- Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao
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p. 1793 - 1796
(2007/10/02)
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- PALLADIUM-CATALYZED ALLYLATION OF KETONES AND ALDEHYDES WITH ALLYLIC CARBONATES VIA SILYL ENOL ETHERS UNDER NEUTRAL CONDITIONS
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Silyl enol ethers are converted to 2-allyl ketones and aldehydes by the reaction with allylic carbonates in the presence of a palladium-phosphine catalyst.
- Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao
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p. 1325 - 1326
(2007/10/02)
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- Geminal Acylation-Alkylation at a Carbonyl Carbon via Regiospecifically Generated Metalloenamines
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A useful procedure for effecting geminal disubstitution at the carbonyl carbon atom of aldehydes and ketones has been developed in which the sequence of reactions results in the replacement of the two carbon-oxygen bonds of the carbonyl function with an acyl group and an alkyl or hydroxyalkyl group.Of particular importance is the facile application of these procedures to the efficient construction of quaternary carbon atoms that bear alkyl appendages containing differentiated functionality.This novel methodology features the initial conversion of carbonyl compounds 1 into the substituted 2-azadienes 10 or 11 by Wittig-Horner reaction.Subsequent reaction of these 2-azadienes produced in situ with n-butyllithium results in the formation of the metalloenamines 12 and 13 (R4 = n-Bu) which undergo reactions with a wide variety of electrophiles to give, after hydrolysis of the intermediate imines, the α-substituted aldehydes 14 or the α-substituted ketones 15 in good of excellent overall yields.New procedures for the annelation of cyclopentenones such as 22 and cyclohexenones 26 at the carbonyl carbon of ketones are described as is an important variant of a directed aldol reaction, 1 --> 28.Although a number of individual manipulations are necessary to effect the geminal disubstitution of a carbonyl functional group, it is generally feasible to execute the entire sequence of reactions in single flask, thereby rendering this methodology very convenient to implement in practice.
- Martin, Stephen F.,Phillips, Gerald W.,Puckette, Thomas A.,Colapret, John A.
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p. 5866 - 5872
(2007/10/02)
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