- Stereoselective Synthesis of Highly Substituted Tetrahydropyrans through an Evans Aldol-Prins Strategy
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A direct and general method for the synthesis of naturally occurring 2,3,4,5,6-pentasubstituted tetrahydropyrans has been developed, employing β,γ-unsaturated N-acyl oxazolidin-2-ones as key starting materials. The combination of the Evans aldol addition and the Prins cyclization allowed the diastereoselective and efficient generation of the desired oxacycles in two fashions: a one-pot Evans aldol-Prins protocol, in which five new σ bonds and five contiguous stereocenters were straightforwardly generated, and a two-step version, which additionally permitted the isolation of β,γ-unsaturated alcohol precursors bearing an N-acyl oxazolidin-2-one in the α position. From these alcohols were also obtained halogenated pentasubstituted tetrahydropyrans as well as 2,3,4,5-tetrasubstituted tetrahydrofurans, shedding light on the mechanism of the process. Computational studies were consistent with the experimental findings, and this innovative Evans aldol-Prins strategy was performed for the preparation of a battery of more than 30 densely substituted tetrahydropyrans, unprecedentedly fused to a 1,3-oxazinane-2,4-dione ring, both in a racemic fashion and in an enantiomeric fashion. These novel molecules were successfully submitted to several transformations to permit simple access to a variety of differently functionalized tetrahydropyrans. Most of these unique molecules were evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and the yeast Candida albicans, and some structure-activity relationships were established.
- álvarez-Méndez, Sergio J.,Fari?a-Ramos, Marta,Villalba, María Luisa,Perretti, Marcelle D.,García, Celina,Moujir, Laila M.,Ramírez, Miguel A.,Martín, Víctor S.
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- Synthetic method γ - nonene lactone
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The invention relates to a synthesis method of γ - nonenolide, belongs to the technical field of perfume synthesis, first steps of adding malonic acid into a four-port flask containing a condensing tube and a water separator, adding piperidine, and then adding heptanal to the 95 - 105 °C condition to raise the temperature and react to obtain the intermediate 1. The second Acetic acid and hydrogen peroxide are mixed, the intermediate 1 is added dropwise, the control temperature is 40 °C, and the intermediate 2 is obtained. The third Intermediate 2, dichloromethane and triethylamine were mixed and acetyl chloride was added dropwise, and after the dropwise addition, γ - nonene lactone was obtained. No solvent is used in first steps of the invention, so that the reaction cost is reduced. The intermediate 1 is closed under the action of acetic acid and hydrogen peroxide, adopts hydrogen peroxide as an oxidant, and has the advantage of environmental friendliness. By replacing methane sulfonyl chloride with acetyl chloride, the use of methane sulfonyl chloride is reduced under the condition of ensuring the yield, the whole reaction process is simple, the route is short, and the raw materials are easily available.
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Paragraph 0019-0021; 0024-0026; 0029-0031; 0034; 0035
(2021/11/10)
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- A practical copper-catalyzed approach to β-lactams: via radical carboamination of alkenyl carbonyl compounds
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Functionalized β-lactams are highly important motifs in synthetic chemistry. We report an efficient and novel approach to the synthesis of β-lactams via a copper(i)-catalyzed cascade process involving C(benzyl)-H radical abstraction, intermolecular alkene addition, and intramolecular amination reaction. Variously substituted alkenes were synthesized from vinylacetic acid, leading to the corresponding β-lactams in moderate to good yields. Preliminary studies indicate that the reaction undergoes a free radical mechanism via a Cu(i)/Cu(ii)/Cu(iii) catalytic cycle.
- Shi, Peng,Wang, Jie,Gan, Zixu,Zhang, Jingyu,Zeng, Runsheng,Zhao, Yingsheng
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supporting information
p. 10523 - 10526
(2019/09/06)
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- Catalytic Regio- and Enantioselective Oxytrifluoromethylthiolation of Aliphatic Internal Alkenes by Neighboring Group Assistance
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Chiral selenide-catalyzed oxytrifluoromethylthiolation of aliphatic internal alkenes by a formally intermolecular strategy is disclosed, affording CF3S 1,3-amino alcohol and 1,3-diol derivatives with high regio-, enantio-, and diastereoselectivities. The reactions are promoted by a neighboring imide or ester group on substrates via a six-membered ring transition state. This assistance strategy is also successfully applied to the regio- and diastereoselective oxyhalofunctionalization of internal alkenes and the conversion of alkynes.
- Xu, Jia,Zhang, Yuanyuan,Qin, Tian,Zhao, Xiaodan
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supporting information
p. 6384 - 6388
(2018/10/09)
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- Structure-Odor Relationships of (Z)-3-Alken-1-ols, (Z)-3-Alkenals, and (Z)-3-Alkenoic Acids
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(Z)-3-Unsaturated volatile acids, alcohols, and aldehydes are commonly found in foods and other natural sources, playing a vital role in the attractiveness of foods but also as compounds with chemocommunicative function in entomology. However, a systematic investigation of their smell properties, especially regarding humans, has not been carried out until today. To close this gap, the odor thresholds in air and odor qualities of homologous series of (Z)-3-alken-1-ols, (Z)-3-alkenals, and (Z)-3-alkenoic acids were determined by gas chromatography-olfactometry. It was found that the odor qualities in the series of the (Z)-3-alken-1-ols and (Z)-3-alkenals changed, with increasing chain length, from grassy, green to an overall fatty and citrus-like, soapy character. On the other hand, the odor qualities of the (Z)-3-alkenoic acids changed successively from cheesy, sweaty via plastic-like, to waxy in their homologous series. With regard to their odor potencies, the lowest thresholds in air were found for (Z)-3-hexenal, (Z)-3-octenoic acid, and (Z)-3-octenal.
- Lorber, Katja,Zeh, Gina,Regler, Johanna,Buettner, Andrea
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p. 2334 - 2343
(2018/03/21)
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- (E)-beta,gamma-alkenyl carboxylic acid derivative and preparation method thereof
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The invention discloses an (E)-beta,gamma-alkenyl carboxylic acid derivative and a preparation method thereof. The preparation method disclosed by the invention comprises the following steps: in an organic solvent, under the condition that a nickel catalyst, a dinitrogen ligand, a reducer and an additive exist, carrying out a carboxylation reaction on an allyl alcohol substrate as shown in formula (II) and carbon dioxide. The preparation method disclosed by the invention is high in selectivity, the raw material reagents are easy to get and has high chemical selectivity and region selectivity, and the derivative is high in yield, high in purity, and low in generation cost and is more applicable for industrial production. (Refer to Specification).
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Paragraph 0083-0086
(2017/08/31)
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- A Facile Method for the Sulfenyllactonization of Alkenoic Acids Using Dimethyl Sulfoxide Activated by Oxalyl Chloride
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A simple approach has been developed for the sulfenyllactonization of alkenoic acids using dimethyl sulfoxide activated with oxalyl chloride, in which methanesulfenyl chloride is proposed as the intermediate.
- Zhang, Ting,Dai, Yifeng,Cheng, Siwei,Liu, Yongguo,Yang, Shaoxiang,Sun, Baoguo,Tian, Hongyu
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p. 1380 - 1386
(2017/03/11)
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- Switchable Site-Selective Catalytic Carboxylation of Allylic Alcohols with CO2
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A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C?OH cleavage and as a C1 source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand employed.
- van Gemmeren, Manuel,B?rjesson, Marino,Tortajada, Andreu,Sun, Shang-Zheng,Okura, Keisho,Martin, Ruben
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supporting information
p. 6558 - 6562
(2017/05/29)
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- Regioselective Ni-Catalyzed Carboxylation of Allylic and Propargylic Alcohols with Carbon Dioxide
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An efficient Ni-catalyzed reductive carboxylation of allylic alcohols with CO2 has been successfully developed, providing linear β,γ-unsaturated carboxylic acids as the sole regioisomer with generally high E/Z stereoselectivity. In addition, the carboxylic acids can be generated from propargylic alcohols via hydrogenation to give allylic alcohol intermediates, followed by carboxylation. A preliminary mechanistic investigation suggests that the hydrogenation step is made possible by a Ni hydride intermediate produced by a hydrogen atom transfer from water.
- Chen, Yue-Gang,Shuai, Bin,Ma, Cong,Zhang, Xiu-Jie,Fang, Ping,Mei, Tian-Sheng
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supporting information
p. 2969 - 2972
(2017/06/07)
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- A 3 - methylthio - γ - method for preparing lactone (by machine translation)
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The invention relates to shown in the following formula of 3 - methylthio - γ - method for preparing lactone: The method comprises the steps: aliphatic aldehyde with malonic acid in dimethyl sulfoxide in acetic acid piperidine salt under the catalytic action of the 100 °C the left and the right reaction, to obtain (E)- 3 - alkane olefine acid, yield 55 - 85%; in the - 78 - 10 °C will b a asian sulphone drop added to the oxalyl chloride in dichloromethane solution, then the (E)- 3 - alkane olefine acid added, at - 78 - 30 °C reaction, to obtain 3 - methylthio - γ - lactone, yield 60 - 82%. (by machine translation)
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Paragraph 0012; 0013
(2017/04/12)
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- Ligand-controlled regiodivergent Ni-catalyzed reductive carboxylation of allyl esters with CO2
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A novel Ni-catalyzed regiodivergent reductive carboxylation of allyl esters with CO2 has been developed. This mild, user-friendly, and operationally simple method is characterized by an exquisite selectivity profile that is dictated by the ligand backbone.
- Moragas, Toni,Cornella, Josep,Martin, Ruben
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p. 17702 - 17705
(2015/02/19)
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- 3-Aminoazetidin-2-one derivatives as N-acylethanolamine acid amidase (NAAA) inhibitors suitable for systemic administration
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N-Acylethanolamine acid amidase (NAAA) is a cysteine hydrolase that catalyzes the hydrolysis of endogenous lipid mediators such as palmitoylethanolamide (PEA). PEA has been shown to exert anti-inflammatory and antinociceptive effects in animals by engaging peroxisome proliferator-activated receptor α (PPAR-α). Thus, preventing PEA degradation by inhibiting NAAA may provide a novel approach for the treatment of pain and inflammatory states. Recently, 3-aminooxetan-2-one compounds were identified as a class of highly potent NAAA inhibitors. The utility of these compounds is limited, however, by their low chemical and plasma stabilities. In the present study, we synthesized and tested a series of N-(2-oxoazetidin-3-yl)amides as a novel class of NAAA inhibitors with good potency and improved physicochemical properties, suitable for systemic administration. Moreover, we elucidated the main structural features of 3-aminoazetidin-2-one derivatives that are critical for NAAA inhibition. Stability is the key: α-Amino-β-lactams were synthesized as amide derivatives, and the effect of the azetidin-2-one ring, the stereochemistry at the α-position, and the functionalization of the α-amino group were studied with regard to N-acylethanolamine acid amidase inhibitory potency and hydrolytic and plasma stability.
- Fiasella, Annalisa,Nuzzi, Andrea,Summa, Maria,Armirotti, Andrea,Tarozzo, Glauco,Tarzia, Giorgio,Mor, Marco,Bertozzi, Fabio,Bandiera, Tiziano,Piomelli, Daniele
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supporting information
p. 1602 - 1614
(2014/07/21)
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- Multistep enzymatic synthesis of long-chain α,ω-Dicarboxylic and ω-hydroxycarboxylic acids from renewable fatty acids and plant oils
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A multistep enzyme catalysis was successfully implemented to produce long-chain α,ω-dicarboxylic and ω-hydroxycarboxylic acids from renewable fatty acids and plant oils. Sebacic acid as well as ω-hydroxynonanoic acid and ω-hydroxytridec-11-enoic acid were produced from oleic and ricinoleic acid. Copyright
- Song, Ji-Won,Jeon, Eun-Yeong,Song, Da-Hyun,Jang, Hyun-Young,Bornscheuer, Uwe T.,Oh, Deok-Kun,Park, Jin-Byung
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supporting information
p. 2534 - 2537
(2013/04/23)
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- Efficient synthesis of the odourant, 2-nonen-4-olide
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A three-step synthesis of 2-nonen-4-olide starting from heptanal is reported. (E)-3-Nonenoic acid, prepared by Knoevenagel condensation of malonic acid and heptanal, was oxidised by performic acid, a process accompanied by lactonisation, to give 3-hydroxynonan-4-olide in 85% yield. This lactone when reacted with MsCl in the presence of Et3N gave, by elimination, 2-nonen-4-olide in 88% yield. The overall yield was 75%. The odour of the product was evaluated by GC-olfactory analysis and sniffing blotter confirming an oily, coconut-like, and rancid odour.
- Dai, Yi-Feng,Tian, Hong-Yu,Sun, Bao-Guo,Sun, Yu-Mei,Chen, Hai-Tao,Liu, Xiao-Yu
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p. 495 - 496
(2012/10/29)
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- Method for regio- and stereoselective synthesis of (E)-Β,γ- unsaturated acids from aldehydes under solvent-free conditions
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Synthesis of (E)-β,-γunsaturated acids from aldehydes with malonic acid has been explored under solvent-free conditions. The modified Knoevenagel condensation reaction with N-methyl morpholine (NMM) as catalyst exhibits highly β,-γ regioselectivity and exclusively E-stereoselectivity. A mechanism accounting for both regio- and stereoselectivity has been proposed and preliminarily studied. Copyright Taylor & Francis Group, LLC.
- Zhang, Shi-Jie,Hu, Wei-Xiao
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experimental part
p. 3093 - 3100
(2010/12/19)
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- A simple method for the alkaline hydrolysis of esters
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A very mild and rapid procedure for the efficient alkaline hydrolysis of esters in non-aqueous conditions has been developed, by the use of dichloromethane/methanol (9:1) as solvent. This method conveniently provides both carboxylic acids and alcohols from the corresponding esters and sodium hydroxide in a few minutes at room temperature. A plausible reaction mechanism is proposed.
- Theodorou, Vassiliki,Skobridis, Konstantinos,Tzakos, Andreas G.,Ragoussis, Valentine
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p. 8230 - 8233
(2008/03/14)
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- Enantioselective syntheses and configuration assignments of γ-chiral butenolides from Plagiomnium undulatum: Butenolide synthesis from tetronic acids
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Both enantiomers of the γ-chiral α,β-dimethylated butyrolactones nat-1 and nat-2 from the moss Plagiomnium undulatum were synthesized stereoselectively through butenolides and tetronic acids, respectively. The configuration of the natural products was determined by GLC comparisons with mono(3-O-acetyl-6-O-tert-butyldimethylsilyl-2-O-methyl) hexakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin as a stationary phase.
- Kapferer, Tobias,Brueckner, Reinhard,Herzig, Axel,Koenig, Wilfried A.
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p. 2154 - 2162
(2007/10/03)
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- β-hydroxy-γ-lactones as chiral building blocks for the enantioselective synthesis of marine natural products
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The enantioselective synthesis of trans-(+)-laurediol, (2S,3S,5R)-5-[(1R)-1-hydroxy-9-decenyl]-2-pentyltetrahydro-3-furanol, and (2S,3S,5S)-5-[(1S)-1-hydroxy-9-decenyl]-2-pentyltetrahydro-3-furanol are described. In addition, a formal synthesis of trans-(-)-kumausyne is also developed. All the synthetic procedures have in common the use of enantiomerically enriched β-hydroxy-γ-lactones, easily available by Sharpless asymmetric dihydroxylation (AD) from the suitable β,γ-unsaturated ester. The use of Katsuki - Sharpless asymmetric epoxidation (AE) as an additional enantioselective reaction provides cyclic compounds of high enantiomeric purity.
- Garcia,Martin,Martin
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p. 1420 - 1428
(2007/10/03)
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- Enantiocontrolled synthesis of C-19 tetrahydrofurans isolated from the marine alga Notheia anomala
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The stereocontrolled synthesis of (2S,3S,5R)-5-[(1R)-1-hydroxy-9- decenyl]-2-pentyltetrahydro-3-furanol and (2S,3S,5S)-5-[(1S)-1-hydroxy-9- decenyl]-2-pentyltetrahydro-3-furanol, both isolated from the brown alga Notheia anomala has been achieved. The req
- García, Celina,Soler, Marcos A.,Martín, Víctor S.
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p. 4127 - 4130
(2007/10/03)
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- SiO2 catalysed expedient synthesis of [E]-3-alkenoic acids in dry media
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Aliphatic aldehydes with α-hydrogens and malonic acid undergo decarboxylative condensation on the surface of SiO2 when subjected to microwave irradiation generating βγ-unsaturated acids in high yields.
- Kumar, H.M. Sampath,Reddy, B.V. Subba,Reddy, E. Jagan,Yadav
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p. 2401 - 2404
(2007/10/03)
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- A Stereospecific Access to Allylic Systems Using Rhodium(II)-Vinyl Carbenoid Insertion into Si-H, O-H, and N-H Bonds
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Rhodium-catalyzed decomposition of α-vinyldiazoesters in the presence of silanes, alcohols, ethers, amines, and thiols have been shown to produce the corresponding α-silyl, α-hydroxy, α-alkoxy, α-amino, and α-thioalkoxy esters in generally good yield with a complete retention of the stereochemistry of the double bond of the diazo precursor. An extension of the process in homochiral series has also been devised using either a chiral auxiliary attached to the ester function or achiral α-vinyldiazoesters and Doyle's chiral catalyst Rh2(MEPY)4. In the former approach, pantolactone as chiral auxiliary gave diastereoselectivities of up to 70%, while the second approach produced the desired allylsilane with ee as high as 72%. On the other hand, Rh2(MEPY)4-catalyzed insertion into the O-H bond of water led to poor or no enantioselectivity in good agreement with recent literature reports.
- Bulugahapitiya, Priyadarshanie,Landais, Yannick,Parra-Rapado, Liliana,Planchenault, Denis,Weber, Valery
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p. 1630 - 1641
(2007/10/03)
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- Aza- and oxacarbonylations of allyl phosphates catalyzed by rhodium carbonyl cluster. Selective synthesis of β,γ-unsaturated amides, esters, and acids
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Rhodium-catalyzed carbonylation of allyl phosphates under CO (20 atm) at 50 deg C proceeds very efficiently in the presence of amines, alcohols, and water to give the corresponding β,γ-unsaturated amides, esters, and acids, respectively.These carbonylations occur with high regioselectivity at the less substituted carbon of allyl unit to give linear β,υ-unsaturated acid derivatives.
- Imada, Yasushi,Shibata, Ou,Murahashi, Shun-Ichi
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p. 183 - 194
(2007/10/02)
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- Novel regioselective hydrogenation of alkadienoic acids caused by the addition of water
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The regioselective hydrogenation of 3,8-nonadienoic acid to 8-nonenoic acid was realized by the addition of water with RhCl[P(p-tolyl)3]3 in benzene at 1 atm hydrogen, whereas in the absence of water the reaction mostly gave 3-nonenoic acid. The novel selectivity is caused by both an accelerating effect of water on the hydrogenation of the 3-position and a retarding effect on that of the 8-position.
- Okano, Temon,Kaji, Mitsunari,Isotani, Satoru,Kiji, Jitsuo
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p. 5547 - 5550
(2007/10/02)
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- Regio- and Stereoselective Ring Opening of ω-Alkenyllactones Using Organocopper Reagents
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New synthetic methods are described for the preparation of (E)-3, (E)-4, and (E)-5-alkenoic acids by the regio- and stereoselective ring opening of β, γ, and δ-lactones with unsaturated substituents at the ω-position using organocopper reagents such as halomagnesium diorganocuprates or Grignard reagents in the presence of copper(I) iodide.Both the organocopper reagents with primary, secondary, tertiary alkyl, and phenyl groups gave the corresponding carbon homologated alkenoic acids in good yields.Alkadienoic acids were also obtained in good yields by the reactions of ω-alkenyllactones with divinyl- and diallylcuprates.Utilizing the ring opening of β-isopropenyl-β-propiolactone, homoterpenoid carboxylic acids were easly obtained in good yields.The ring opening of β-(1-chlorovinyl)-β-propiolactone afforded 4-chloro-3-alkenoic acids which were easly transformed to 4-oxoalkanoic acids and 4-oxo-2-alkenoic acids.
- Kawashima, Masatoshi,Sato, Toshio,Fujisawa, Tamotsu
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p. 3255 - 3264
(2007/10/02)
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- MODIFIED KNOEVENAGEL CONDENSATIONS. SYNTHESIS OF (E)-3-ALKENOIC ACIDS.
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Condensation of aliphatic aldehydes with a three molar excess of malonic acid and 0.001 mole piperidinium acetate in refluxing xylene, with continuous removal of the water formed, gave almost exclusively (E)-3-alkenoic acids, in good yield (60-85percent) and of high stereochemical purity (95-99percent).
- Ragoussis, Nikitas
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- REGIOSELECTIVITY OF β-VINYL-β-PROPIOLACTONE TOWARD VARIOUS NUCLEOPHILES
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Regioselectivity in the reaction of β-vinyl-β-propiolactone with various nucleophiles was found to depend on the hard and soft acid and base (HSAB) principle.A hard base such as methoxide ion attacked the acyl carbon exclusively, while the nucleophilic at
- Fujisawa, Tamotsu,Sato, Toshio,Takeuchi, Masashi
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- A CONVENIENT METHOD FOR THE SYNTHESIS OF (E)-3-ALKENOIC ACIDS BY A REGIO- AND STEREOSELECTIVE REACTION OF β-VINYL-β-PROPIOLACTONE WITH ORGANOCOPPER REAGENTS
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β-Vinyl-β-propiolactone reacts regio- and stereoselectively with Grignard reagents in the presence of copper(I) catalyst or with diorganocuprates to afford (E)-3-alkenoic acids in high yields.
- Sato, Toshio,Takeuchi, Masashi,Itoh, Toshiyuki,Kawashima, Masatoshi,Fujisawa, Tamotsu
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p. 1817 - 1820
(2007/10/02)
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- 8,12-Dialkyl-PGE, and PGF1α
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Prostaglandins E1 -type and F1 -type compounds of the formula EQU1 wherein R is hydrogen or a hydrocarbyl group containing from 1 to 12 carbon atoms, inclusive, wherein W is EQU2 or O =, wherein R7, R8, R9, R10, R11, R12, R13, and R14 are hydrogen or alkyl of 1 to 4 carbon atoms, inclusive, provided (1) that at least one of R7, R8, R9, R10, R11, R12, R13, and R14 is alkyl (2) that when R13 is alkyl, at least one of R7, R8, R9, R10, R11, R12, and R14 is alkyl, and (3) that when R7 is alkyl or thwn R7 and R8 are alkyl, at least one of R9, R10, R11, R12, R13, and R14 is alkyl; and the enantiomers and racemic mixtures thereof. These are useful for the same pharmacological purposes as the unsubstituted prostaglandins.
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