- Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)
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The use of mono-substituted malonic acid half oxyesters (SMAHOs) has been hampered by the sporadic references describing their preparation. An evaluation of different approaches has been achieved, allowing to define the best strategies to introduce diversity on both the malonic position and the ester function. A classical alkylation step of a malonate by an alkyl halide followed by a monosaponification gave access to reagents bearing different substituents at the malonic position, including functionalized derivatives. On the other hand, the development of a monoesterification step of a substituted malonic acid derivative proved to be the best entry for diversity at the ester function, rather than the use of an intermediate Meldrum acid. Both these transformations are characterized by their simplicity and efficiency, allowing a straightforward access to SMAHOs from cheap starting materials.
- Condon, Sylvie,Le Gall, Erwan,Pichon, Christophe,Presset, Marc,Xavier, Tania
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supporting information
p. 2085 - 2094
(2021/09/02)
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- Visible-Light-Enhanced Cobalt-Catalyzed Hydrogenation: Switchable Catalysis Enabled by Divergence between Thermal and Photochemical Pathways
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The catalytic hydrogenation activity of the readily prepared, coordinatively saturated cobalt(I) precatalyst, (R,R)-(iPrDuPhos)Co(CO)2H ((R,R)-iPrDuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene), is described. While efficient turnover was observed with a range of alkenes upon heating to 100 °C, the catalytic performance of the cobalt catalyst was markedly enhanced upon irradiation with blue light at 35 °C. This improved reactivity enabled hydrogenation of terminal, di-, and trisubstituted alkenes, alkynes, and carbonyl compounds. A combination of deuterium labeling studies, hydrogenation of alkenes containing radical clocks, and experiments probing relative rates supports a hydrogen atom transfer pathway under thermal conditions that is enabled by a relatively weak cobalt-hydrogen bond of 54 kcal/mol. In contrast, data for the photocatalytic reactions support light-induced dissociation of a carbonyl ligand followed by a coordination-insertion sequence where the product is released by combination of a cobalt alkyl intermediate with the starting hydride, (R,R)-(iPrDuPhos)Co(CO)2H. These results demonstrate the versatility of catalysis with Earth-abundant metals as pathways involving open-versus closed-shell intermediates can be switched by the energy source.
- Mendelsohn, Lauren N.,MacNeil, Connor S.,Tian, Lei,Park, Yoonsu,Scholes, Gregory D.,Chirik, Paul J.
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p. 1351 - 1360
(2021/02/01)
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- FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
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The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
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Paragraph 0175; 0185-0186; 0292-0294
(2021/06/22)
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- Enantioselective α-Amination of Acyclic 1,3-Dicarbonyls Catalyzed by N-Heterocyclic Carbene
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Herein, we describe a method for the catalytic enantioselective α-amination of α-substituted acyclic 1,3-ketoamides and 1,3-amidoesters that affords the products possessing N-substituted quaternary stereocenters with a chiral N-heterocyclic carbene (NHC). The reaction is based on the utilization of an intrinsic Br?nsted base characteristic of NHC that enables the catalytic formation of a chiral ion pair comprising the enolate and the azolium ion. A series of challenging open-chain α-substituted 1,3-dicarbonyls are aminated via this method with ee's of ≤99%.
- Santra, Surojit,Maji, Ujjwal,Guin, Joyram
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supporting information
p. 468 - 473
(2020/02/04)
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- “Backdoor Induction” of Chirality: Trans-1,2-cyclohexanediamine as Key Building Block for Asymmetric Hydrogenation Catalysts
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This paper describes the synthesis and characterization of 21 chiral monodentate ligands L, assembled of three building blocks utilizing amide bonds: a metal binding triphenylphosphine, a chiral cyclic diamine and an additional substituent for fine-tuning the steric and/or electronic properties. Cis square-planar metal complexes of RhI and PtII with ML2 stoichiometry have been prepared and characterized by spectroscopic methods (NMR, IR, UV-Vis, CD) and DFT calculations. A key feature of the metal complexes is a prochiral metal coordination sphere and “backdoor induction” of chirality from a distant chiral source via an outer-coordination sphere, well-defined by aromatic stacking and hydrogen-bonding. The rhodium complexes were used as catalysts in asymmetric hydrogenation of α,β-dehydroamino acids with excellent yield and selectivity (up to 97 % ee), strongly supporting the “backdoor induction” hypothesis.
- Glasovac, Zoran,Kirin, Sre?ko I.,Kokan, Zoran,Opa?ak, Sa?a,Peri?, Berislav
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supporting information
p. 2115 - 2128
(2019/01/04)
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- Copper-Catalyzed Dehydrogenative Diels-Alder Reaction
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A practical and effective copper-catalyzed dehydrogenative Diels-Alder reaction of gem-diesters and ketone with dienes has been established. The active dienophiles were generated in situ via a radical-based dehydrogenation process, which reacted with a wide variety of dienes to afford various polysubstituted cyclohexene derivatives in good to excellent yields.
- Jiang, Bing,Liang, Qiu-Ju,Han, Yu,Zhao, Meng,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 3215 - 3219
(2018/06/11)
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- 2 - methyl malonic acid diester synthetic method of the compound
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The invention discloses a synthetic method of 2-diester methylmalonate compounds, and relates to the technical field of carboxylic ester preparation. The synthetic method comprises steps as follows: C, sulfonic acid 2-ethyl N-cyanoethanimideate IV and cyanide react under the action of a solvent and a catalyst, and 2-methyl malononitrile V is obtained; D, 2-methyl malononitrile V and ROH react under the action of the solvent and concentrated sulfuric acid, and products of 2-diester methylmalonate compounds I are obtained, wherein MCN is cyanide, M is Na or K, ROH is alkyl alcohol, alkenyl alcohol or a fluoride group containing alcohol, is benzyl alcohol or benzyl alkyl, halogen or nitro substituted benzyl alcohol, or is phenol or C1-C5 containing alkyl, halogen or nitro substituted phenol. The method is unique, the reaction conditions are mild, the reaction process is basically free of by-products, the yield is high, adopted raw materials have extensive sources, and acetaldehyde can be used as the raw material; the synthetic method is applicable to industrial production.
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Paragraph 0043-0045
(2017/08/10)
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- Ester derivative industrial production process
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The present invention provides an ester derivative industrial production process which is characterized in that a monoester or a diester derivative is obtained by reaction of a compound A and carbon monoxide or carbon dioxide under the effect of a catalyst; the production process is simple, and is different from complex production ways and demanding production conditions in the prior art, and the target ester derivative product can be synthesized by one step. The production process and synthetic routes are optimized, so that the production process is fewer in side effects, convenient in post treatment, mild in production conditions, and suitable for industrial production modes.
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-
Paragraph 0049; 0050; 0051; 0052; 0053
(2016/10/10)
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- Copper(II) triflate catalyzed amination and aziridination of 2-Alkyl substituted 1,3-dicarbonyl compounds
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A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu(OTf)2 + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhI=NTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic C-H bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2-3 equiv was discovered to result in preferential formal aziridination of the C-C bond of the 2-alkyl substituent of the starting material and formation of the aziridine product.
- Ton, Thi My Uyen,Tejo, Ciputra,Tiong, Diane Ling Ying,Chan, Philip Wai Hong
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experimental part
p. 7344 - 7350
(2012/06/16)
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- Behaviour of enaminomalonates and enamidomalonates under various reductive conditions: a novel synthetic approach to N-acetyl-N-aryl β-amino acids
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The behaviour of enaminomalonates and their deprotection to amines under various reductive conditions is described. A new synthetic approach to N-aryl-N-acetyl-β-amino acids using heterogeneous catalytic hydrogenation has been discovered.
- Sol?an, Tomá?,Jakubec, Pavol,Prónayová, Nade?da,Milata, Viktor
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p. 2631 - 2633
(2008/09/19)
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- The Co(I) induced methylmalonyl-succinyl rearrangement in a model for the coenzyme B12 dependent methylmalonyl-CoA mutase.
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The rearrangement of 2-bromomethyl-2-methylmonothiomalonates to succinyl derivatives was found to take place in quantitative yields in the presence of one molar equivalent of Co(I) generated by the reduction of heptamethyl Co(II)yrinate perchlorate with NaBH4 or electrochemically. The chiral thiomalonate gave racemic succinate.
- Sun, Fangping,Darbre, Tamis
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p. 3154 - 3159
(2007/10/03)
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- Chemo-enzymatic synthesis of chiral 2-substituted succinic acid derivatives
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Prochiral discrimination by the biocatalyst Alcalase, an enzyme preparation of subtilisin Carlsberg, was used to effect enantio- and regioselective monohydrolysis of a variety of (RS)-2-substituted succinate diesters to afford the corresponding half esters in modest to excellent enantiomeric excesses (>99%). Exploitation of malonate chemistry, as well as recycling of the unhydrolyzed isomer from the enantioselective hydrolysis, has resulted in a process which is both practical and economical.
- Bailey, Murray D.,Halmos, Ted,Adamson, Dan,Bordeleau, Josee,Grand-Maitre, Chantal
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p. 3285 - 3295
(2007/10/03)
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- Michael reactions promoted by η1-O-enolatoruthenium(II) complexes derived from Ru(cod)(cot), diphosphine, and dimethyl malonate
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The Michael reaction of 1,3-dicarbonyls with α,β-unsaturated esters and nitriles has been carried out very efficiently, under mild and neutral conditions, in the presence of a catalytic amount of trans-hydrido(η1-O- enolato) ruthenium(II) complex (2), which is prepared from the reaction of Ru(cod)(cot) (1) (cod = cycloocta-1,5-diene; cot = cycloocta-1,3,5-triene) with dimethyl malonate in the presence of 1,2-bis(diphenylphosphino)ethane (dpe).
- Alvarez, Salvador G.,Hasegawa, Sachi,Hirano, Masafumi,Komiya, Sanshiro
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p. 5209 - 5212
(2007/10/03)
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- Palladium(II)-Catalyzed Asymmetric Acetalization of Alkenes
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The terminal olefinic carbon of N-methaacryloyl-2-oxazolidinones is smoothly acetalized by alcohols in the presence of PdCl2 catalyst.The use of 4(S)-isopropyl-, phenyl-, and tert-butyl-2-oxazolidinones as the chiral auxiliary resulted in the formation of the corresponding (2'S)-acetals in 61, 80, and 95percent de, respectively.Reductive removal of the auxiliary with LiAlH4 followed by deacetalization produced (R)-3-hydroxy-2-methylpropanal.The enantiomer of this compound, derived from 4(R)-substituted oxazolidinones, served as a building block for synthesizing a 1β-methylcarbapenem precursor in high enantiomeric excess.In the acetalization of 3',3'-dideuteriated methacryloyl-4-isopropyloxazolidinone with MeOH, one D-atom on the terminal olefinic carbon stereoselectively migrated to the chiral center in the product acetal.On the basis of this 1,2-hydride migration and the conformational preference of the methacryloyl moiety, the reaction pathway and the mechanism of the diastereoselection are discussed.
- Hosokawa, Takahiro,Yamanaka, Toshio,Itotani, Motohiro,Murahashi, Shun-Ichi
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p. 6159 - 6167
(2007/10/03)
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- Evidence for Ketene Intermediates in the Decarbonylation of 2,4-Dioxo Acids and Esters and 2-Oxobutanedioic Acid Esters
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The mechanism by which α,γ-dioxo carboxylic acid esters 1 and 2-oxobutanedioic acid diesters 2 lose CO was explored.The compounds, 5,5-dimethyl-2,4-dioxohexanoic acid ethyl ester, 1a, α-2-dioxocyclohexaneacetic acid ethyl ester, 1b, and α,1-dioxotetrahydro-2-naphthaleneacetic acid ethyl ester, 1c, lose CO at 170-190 deg C to yield the corresponding β-keto esters 3a-c.When compounds 1 or the parent acids 4 were heated to 170-190 deg C with water in a sealed reactor, they yielded ketones resulting from replacement by H of C(O)CO2R from 1 or C(O)CO2H from 4. β-Ketoesters suffered replacement by H of the carbethoxy group to yield the corresponding ketones when heated with water at about 105 deg C.Acylketenes, such as 4,4-dimethyl-1-pentene-1,3-dione, 6a, 2-oxo-cyclohexylidenemethanone, 6b, 1-oxotetrahydro-2-naphthylidenemethanone, 6c, 3-methyl-1-butene-1,3-dione, 6d, and 1-butene-1,3-dione, 6e, are implicated as the common intermediates that react with water to form β-keto acids that subsequently decarboxylateto yield the ketones 5.Intense IR frequencies in the region of 2120-2140 cm-1, characteristic of ketenes, are observed when 1, 2, or 3 is subjected to GC-FTIR analysis with the injector and light pipe at 280 deg C.Loss of carbon monoxide and alcohol at high temperature is required to form 6 from 1, while only the loss of alcohol at lower temperature is needed to form 6 from 3.
- Emerson, David W.,Titus, Richard L.,Gonzalez, Rowena M.
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p. 5301 - 5307
(2007/10/02)
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- 30. On the Regioselectivity Control in the Palladium-Catalyzed Hydro-alkoxycarbonylation of α,β-Unsaturated Esters
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The regioselectivity of the hydro-alkoxycarbonylation of methyl acrylate, methacrylate, and crotonate catalyzed by complexes (L = phosphine ligands) can be largely controlled by variation of the ligands.PPh3 promotes preferential carbonylation a
- Consiglio, Giambattista,Nefkens, Sylvia C. A.,Pisano, Carmelina,Wenzinger, Fritz
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p. 323 - 325
(2007/10/02)
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- Ruthenium-catalyzed Reductive Alkylation of Active Methylene Compounds with Aldehydes under Synthesis Gas
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Active methylene compounds undergo reductive alkylation with aldehydes when heated at 135-230 deg C under synthesis gas of 100 atm in the presence of ruthenium carbonyl.
- Abe, Fujio,Hayashi, Teruyuki,Tanaka, Masato
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p. 765 - 768
(2007/10/02)
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- Process to produce silyl ketene acetals
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A process for the preparation of silyl ketene acetals of the formulae, from the reaction of a malonate compound with a triorganohalosilane in the presence of an alkali metal. The malonate compounds are dialkyl dialkylmalonates, bis(trialkylsilyl) dialkylmalonates, and dialkylmalonic acids. The triorganohalosilane is present in stoichiometric excess relative to the malonate compounds. Silyl ketene acetals are isolated and separated.
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- Alkylated or alkenylated malonic acid or its derivatives having a fluorine
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An alkylated or alkenylated malonic ester having a fluorine containing aliphatic substituent and derivatives thereof as expressed by the following general formula: STR1 where Rf is a fluorine containing aliphatic group, R is an aliphatic group, or hydrogen or alkali metal atom, and R' is an unsubstituted or substituted aliphatic group. And a method to trap the enolate ion of a malonic ester having a fluorine containing aliphatic substituent as expressed by the following general formula, where Rf is a fluorine containing aliphatic group and R is an aliphatic group, hydrogen or alkali metal atom, wherein said malonic ester is converted under the action of a weaker base and/or fluoride ion to a fluorine containing enolate ion to be trapped as expressed by the following general formula: where Rf and R are the same as above.
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- THE RELEVANCE OF ESTER EXCHANGE IN OXALACETIC ESTERS TO THE DECARBONMONOXYLATION REACTION
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Oxalacetic esters undergo ester exchange at 120 deg C, at which temperature loss of CO does not occur.A new mechanism is proposed for the decarbonmonoxylation reaction.
- Fitzhugh, Anthony L.,Strauss, Richard S.,Brewer, Elizabeth N.,Glassman, Steven D.,Jones, Maitland
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p. 3911 - 3914
(2007/10/02)
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- Enol Ethers, XIV. Acylation of Keto Enol Ethers with Malonyl Dichloride - A New Synthesis of Phloroglucinols
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Phloroglucinols 4 and/or 4-hydroxy-2H-pyran-2-ones 5 are formed from keto enol ethers 1 and malonyl dichloride (2a) in high yields.Since the pyranones 5 can be smoothly converted into phloroglucinols, the reaction of 1 with 2a represents a new, facile synthetic route to phloroglucinols.The reaction proceeds via formation of a chloro carbonyl ketene 8 and its subsequent reaction with 1.The product ratio 4:5 is rationalized in terms of substituent effects in the enol ether substrate.
- Effenberger, Franz,Schoenwaelder, Karl-Heinz
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p. 3270 - 3279
(2007/10/02)
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- 1-pyrrole from Trimethyl(1-pyrrolyl)ammonium Ion
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Trimethyl(1-pyrrolyl)ammonium iodide (5a) and the corresponding p-toluenesulfonate 5b are transformed by strong bases into 1-pyrrole (9), i.e. into a N-Mannich base, a type of compound novel in the pyrrole series.In this reaction, which is very fast in DMSO the cation of compounds 5 is deprotonated to form the nitrogen ylide 6.The latter undergoes a Stevens-type rearrangement to 9.Several facts, namely the negative outcome of a cross-reaction experiment with 3,4-dimethylpyrrole and of an attempt to obtain 9 from pyrrole and dimethyl(methylidene)ammonium iodide in the presence of one equivalent of sodium methoxide, as well as unsuccessful CIDNP studies point to a rearrangement mechanism via the contact ion pair 12.
- Zeltner, Peter,Bernauer, Karl
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p. 1860 - 1864
(2007/10/02)
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- The Allopolarization Principle and its Applications, IV. Substituent Effects in the Methylation of Enolate Anions
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The ratio of O- and C-methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethylketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents.In some cases the influence of solvents, concentration and temperature has also been studied.
- Gompper, Rudolf,Vogt, Hans-Hubert
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p. 2866 - 2883
(2007/10/02)
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