Showing papers on "Grignard reaction published in 2015"
TL;DR: Using 2‐iodophenyl arylsulfonates as benzyne precursors, Arynes participate in three‐component coupling reactions with N, S, P, and Se functionalities to yield 1,2‐heteroatom‐difunctionalized arenes.
Abstract: Arynes participate in three-component coupling reactions with N, S, P, and Se functionalities to yield 1,2-heteroatom-difunctionalized arenes. Using 2-iodophenyl arylsulfonates as benzyne precursors, we could effectively add magnesiated S-, Se-, and N-nucleophilic components to the strained triple bond. In the same pot, addition of electrophilic N, S, or P reagents and a copper(I) catalyst trapped the intermediate aryl Grignard to produce a variety of 1,2-difunctionalized arenes.
75 citations
TL;DR: A general iodine-based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates.
Abstract: The radical nature of iron-catalyzed cross-coupling between Grignard reagents and alkyl halides has been studied by using a combination of competitive kinetic experiments and DFT calculations. In contrast to the corresponding coupling with aryl halides, which commences through a classical two-electron oxidative addition/reductive elimination sequence, the presented data suggest that alkyl halides react through an atom-transfer-initiated radical pathway. Furthermore, a general iodine-based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates.
53 citations
TL;DR: In this paper, a novel organosiloxane containing a thermally cross-linkable benzocyclobutene group was successfully synthesized through a one-pot Grignard reaction procedure.
44 citations
TL;DR: Arylmethyl-substituted pyrrolidines and tetrahydrofurans were produced by FeCl2-catalyzed tandem cyclization and cross-coupling reactions of alkyl iodides and aryl Grignard reagents as discussed by the authors.
24 citations
TL;DR: In this paper, a five-week miniproject is described for an upper-division experimental organic chemistry course, which includes synthesis of a phenylboronic acid via a Grignard reaction and its use in a Suzuki-Miyaura cross-coupling reaction.
Abstract: A five-week miniproject is described for an upper-division experimental organic chemistry course. The activities include synthesis of a phenylboronic acid via a Grignard reaction and its use in a Suzuki–Miyaura cross-coupling reaction. Technical skills and concepts normally presented in practical organic chemistry courses are covered, including the use of an inert atmosphere (Schlenk tube technique), separation of mixtures (filtration), melting range determination, infrared (IR) spectrum, stoichiometric calculations and gas chromatography techniques.
24 citations
TL;DR: In this paper, an efficient total synthesis of (+)-petromyroxol, a marine natural product, was described using Sharpless asymmetric dihydroxylation (AD), intramolecular SN2 cyclization and stereoselective Grignard reaction as key steps.
19 citations
TL;DR: In this article, an efficient method for the synthesis of N-(hetero)aryl carbazoles, useful compounds for functional materials, was reported, where the reaction conditions and a postulated catalytic cycle for the reaction were discussed.
Abstract: An efficient method for the synthesis of N-(hetero)arylcarbazoles, useful compounds for functional materials, is reported. Various (hetero)aryl chlorides reacted with N-carbazolylmagnesium chloride in the presence of a palladium catalyst (0.05 to 0.2 mol%) prepared from allylpalladium(II) chloride dimer {[PdCl(allyl)]2} and di-tert-butyl(2,2-diphenyl-1-methylcyclopropan-1-yl)phosphine (cBRIDP) under mild conditions (110 °C) in a short period of time (15 min to 2 h) to give N-(hetero)arylcarbazoles in high yields. The reactions of bromochlorobenzenes proceeded in favour of the bromo group to afford N-(chlorophenyl)carbazoles in a highly selective manner. Functional materials for use in organic light-emitting diodes, such as mCP, 26mcPy, CBP and TCB, were also obtained in high yields within 15 min by the reaction of (hetero)aryl polyhalides. Optimization of the reaction conditions and a postulated catalytic cycle for the reaction are also discussed.
18 citations
TL;DR: Conversion of ester moieties into 4-bromophenyl groups was effected by means of a four-step protocol: a Grignard reaction of the ester with allylmagnesium halides, a ring-closing metathesis, dibromocyclopropanation, and an electrocyclic reaction of.
16 citations
TL;DR: A new synthetic strategy to cyclophanes containing thiophene and indole moieties via Grignard addition, Fischer indolization and ring-closing metathesis as key steps is demonstrated.
Abstract: We demonstrate a new synthetic strategy to cyclophanes containing thiophene and indole moieties via Grignard addition, Fischer indolization and ring-closing metathesis as key steps.
14 citations
TL;DR: In this paper, the Kumada cross coupling reaction was investigated by developing a reliable, efficient procedure for the Grignard reagent and its subsequent cross-coupling reaction, which was successfully demonstrated at the multikilogram (50 kg) scale.
11 citations
TL;DR: A simple synthetic strategy to C 2-symmetric bis-spiro-pyrano cage compound 7 involving ring-closing metathesis is reported and the synthesis of an unprecedented octacyclic cage compound through intramolecular Diels–Alder reaction as a key step is described.
Abstract: A simple synthetic strategy to C 2-symmetric bis-spiro-pyrano cage compound 7 involving ring-closing metathesis is reported. The hexacyclic dione 10 was prepared from simple and readily available starting materials such as 1,4-naphthoquinone and cyclopentadiene. The synthesis of an unprecedented octacyclic cage compound through intramolecular Diels-Alder (DA) reaction as a key step is described. The structures of three new cage compounds 7, 12 and 18 were confirmed by single crystal X-ray diffraction studies.
TL;DR: A series of novel 1-hydroxycycloalkyl- and cycloalkenylthiophenes (4a−4≿, 4e, 6b, 6d, 6e) were synthesized via Grignard reaction as discussed by the authors.
Patent•
11 Mar 2015
TL;DR: In this article, a preparation method for flurogestone acetate is presented, where the starting material is low in cost, readily available and stable; the whole process flow is simple; a low-temperature Grignard side chaining is adopted, so that high-temperature esterification in the presence of 9(11) epoxy is avoided, side reaction is greatly reduced, the total yield is greatly improved, production cost is lowered, and the preparation method is more suitable for industrial production.
Abstract: The invention discloses a preparation method for flurogestone acetate. A compound I, i.e. 9alpha-OH-AD, is taken as a starting raw material, and a compound VIII (16alpha-acetate-9-fluoro-11beta-hydropregna-4-ene-3,20-diketone), i.e. the flurogestone acetate, is prepared by elimination reaction, cyano substitution reaction, ketal protection reaction, esterification reaction, Grignard reaction, bromization epoxidation reaction and fluorination reaction. According to the preparation method, the starting material is low in cost, readily available and stable; the whole process flow is simple; a low-temperature Grignard side chaining is adopted, so that high-temperature esterification in the presence of 9(11) epoxy is avoided, side reaction is greatly reduced, the total yield is greatly improved, production cost is lowered, and the preparation method is more suitable for industrial production.
TL;DR: In this article, four possible stereoisomers of a model compound of highly O-bearing bisabolane sesquiterpenes were synthesized and their NMR spectra were compared.
Abstract: Four possible stereoisomers of a model compound of highly O-bearing bisabolane sesquiterpenes were synthesized and their NMR spectra were compared. Starting from isopulegol, allylic oxidation and Grignard reaction afforded a mixture of alcohols at C(8), which was separated. After metathesis reaction, both α- and β-epoxides were obtained via non-stereoselective epoxidation, while VO(OiPr)3-catalyzed epoxidation afforded a single diastereoisomer selectively. NMR Spectra of twelve synthesized compounds, four stereoisomers of acetates, isobutyrates, and tiglates, were measured. A difference between C(8α)- and C(8β)-acyloxy isomers was observed in the δ-values of HC(8) in CDCl3. Within the 8β-acyloxy compounds, the α- and the β-epoxides were distinguished by either the J-value of HC(8) or the chemical shift of CH2(9). Within the 8α-acyloxy compounds, two epoxide isomers were distinguished by the J-value of HC(10) in C6D6 or in CD3OD.
Patent•
09 Dec 2015
TL;DR: In this article, an epoxiconazole intermediate 1-chloro-3-(2-chlorophenyl)-2-(4-fluorophenyl) 2-propanol synthesis process is described.
Abstract: The present invention discloses an epoxiconazole intermediate 1-chloro-3-(2-chlorophenyl)-2-(4-fluorophenyl)-2-propanol synthesis process, and belongs to the technical field of fine chemical industry. According to the process, 2-chlorobenzyl chloride and 2-chloro-4'-fluoroacetophenone are adopted as raw materials, diethoxymethane and toluene are adopted as solvents, and a two-step reaction comprising as a Grignard reaction and a nucleophilic addition reaction is performed to obtain the target product. According to the present invention, the high yield intermediate is obtained while the process operation is simplified, the raw material cost and the production cost are reduced, the environmental pollution is reduced, and the safety requirements of the industrial scale-up production are met.
TL;DR: In this paper, a comparative study of the titanium-mediated cyclopropanation of (benzyloxy)acetonitrile and Boc-protected cyanohydrin using unsaturated Grignard reagents (but-3-enyl- and pent-4enylmagnesium bromides) is described.
Abstract: A comparative study of the titanium-mediated cyclopropanation of (benzyloxy)acetonitrile and Boc-protected cyanohydrin using unsaturated Grignard reagents (but-3-enyl- and pent-4-enylmagnesium bromides) is described. The best conditions to provide the cis and trans isomers of cyclopropylamines bearing unsaturation were identified and the alkene moiety was subjected to chemical modifications, as shown by the synthesis of orthogonally protected cis - and trans -2,3-methanolysine, cis -2,3-methanoornithine, and cis -2,3-methanohomolysine.
Patent•
10 Jun 2015
TL;DR: In this article, the Grignard reaction of a terpene derived carboxylate with methyimagnesium bromide is described as follows: 2,3,7-trimethyloct-6-en-2-ol, 2, 3, 7- trimethyl oct-7-deconvocalized oct-6en-decomposition, or a mixture thereof.
Abstract: The invention relates to terpene-derived compounds, such as acids, esters thereof, produced by ozonolysis of terpenes and to alcohols, amide, nitriles derived therefrom, as well as to processes for synthesizing them. Specifically 2,3,7-trimethyloct-6-en-2-ol, 2,3,7- trimethyloct-7-en-2-ol, or a mixture thereof, produced by Grignard reaction of a terpene derived carboxylate with methyimagnesium bromide is disclosed.
TL;DR: In this paper, a combined synthetic and computational study on the addition of Grignard reagents RMgBr/RMgI (R = Me, Et) to various sterically rigid N-(aryl)imino-acenapthenone (Ar-BIAO) ligands was presented.
Abstract: We present a combined synthetic and computational study on the addition of Grignard reagents RMgBr/RMgI (R = Me, Et) to various sterically rigid N-(aryl)imino-acenapthenone (Ar-BIAO) (Ar = 2,6-iPr2C6H3 (1), 2,6-Me2C6H3 (2), and 2,4,6-Me3C6H2 (3) ligands). In the experimental method, when compounds 1–3 were treated with RMgBr (R = Me, Et) at room temperature, the corresponding racemic N-(aryl)imino-acenapthylene-1-ol (Ar-BIAOH) compounds (Ar = 2,6- iPr2C6H3, R = Me (1a), Et (1b); Ar = 2,6-Me2C6H3, R = Me (2a), Et (2b); and Ar = 2,4,6-Me3C6H2, R = Me (3a), Et (3b)) were obtained in yields up to 82 %. The Ar-BIAOH compounds were characterized by spectroscopic and combustion analyses. The solid state structures of compounds 1a–3a were established by single-crystal X-ray diffraction analysis. To model the transition state of the Grignard reaction with asymmetrical and sterically rigid Ar-BIAO ligands having three fused rings containing exo-cyclic carbonyl and imine functionalities, we carried out computational analysis. During our study, we have considered the gas phase addition of CH3MgBr to 2 and the model system of 2-(methylimino)pentanone (2′). We have carried out ab initio (HF/3–21G*) and density functional theory calculations with the hybrid density functional B3LYP/6–311+G(2d,p) to probe two major aspects: (1) the stability of an intra-molecular chelation involving magnesium, carbonyl oxygen, and imine nitrogen and (2) to suggest a probable transition state and a mechanistic pathway. The computational investigation suggests the formation of a tetra-coordinated magnesium complex as the transition state for the Grignard reaction.
TL;DR: A simple, efficient and eco-friendly process for the synthesis in good yield of azoxystrobin from 2-bromophenol has been developed using phenolic hydroxyl protection, Grignard reaction, Suzuki cros....
Abstract: A simple, efficient and eco-friendly process for the synthesis in good yield of azoxystrobin from 2-bromophenol has been developed using phenolic hydroxyl protection, Grignard reaction, Suzuki cros...
TL;DR: In this paper, three new types of tartaric acid, lactic acid and TADDOL derived compounds featuring a linear shaped central backbone and terminally attached functional units corresponding to the above substance classes have been developed.
TL;DR: A novel method for in situ Grignard reaction using magnesium powder and CFCl3 for synthesis of dichlorofluoromethyl aromatic alcohols is presented.
Abstract: Synthetic modification of trichlorofluoromethane (CFCl3) to non-volatile and useful fluorinated precursors is a cost-effective and an environmentally benign strategy for the safe consumption/destruction of the ozone depleting potential of the reagent. In this report, we present a novel method for in situ Grignard reaction using magnesium powder and CFCl3 for synthesis of dichlorofluoromethyl aromatic alcohols.
Patent•
22 Apr 2015
TL;DR: In this paper, a method for preparing an arylboronic acid compound using a Grignard reaction was described, where the Grignards reaction was conducted in an anhydrous organic solvent, a magnesium rod and one to two drops of iodine were added.
Abstract: The invention provides a method for preparing an arylboronic acid compound shown in the formula (I). The method includes the following steps that (1) a Grignard reagent is prepared, wherein in an anhydrous organic solvent, a magnesium rod and one to two drops of iodine are added, a substance shown in a formula (II) and acquired by dissolving the anhydrous organic solvent at certain concentration is dripped, a Grignard reaction is conducted, and the Grignard reagent is generated; (2) a compound shown in the formula (I) is prepared, wherein the Grignard reagent is dripped into an organic solution shown in a formula (III) and acquired by dissolving the anhydrous organic solvent at certain concentration, a synthetic reaction is conducted, and after the reaction is finished, the compound shown in the formula (I) is acquired after hydrolysis and aftertreatment, wherein the formula (I), the formula (II) and the formula (III) are shown in the specification, and R1, B, O and R2 are defined in the specification.
Patent•
04 Feb 2015
TL;DR: In this article, a side-chain-type difluoro monomer and a synthesis method of the monomer are described. But the method is not suitable for polymers.
Abstract: The invention discloses a side-chain-type difluoro monomer and a synthesis method thereof. A structure formula of the monomer is described as follows, wherein X is represented as CH3 or OCH3 and n is an integer between 1 and 3. The monomer is prepared with 3,5-dimethylbromobenzene as a raw material and through a Grignard reaction, a nucleophilic addition addition, a bromination reaction and a coupled reaction. The side-chain-type difluoro monomer contains a polymerizable difluoro group and functionalizable methyl or methoxy. Through a polycondensation reaction and functional group transition, a quaternized or sulfonated polymer can be prepared from the side-chain-type difluoro monomer. A functional polymer can be employed as a polymer electrolyte membrane material of a fuel cell.
Patent•
26 Aug 2015
TL;DR: In this article, the Grignard reaction is adopted, hydroxyl protection ketone reacts with n-propylamine to prepare draxxin, so that the harsh reaction condition during the carbonyl epoxidation process is avoided.
Abstract: The invention discloses a preparation method of draxxin. The preparation method comprises the following steps: the Grignard reaction is adopted, hydroxyl protection ketone reacts with a Grignard reagent, a chloromethyl is introduced in the position of a carbonyl, the carbonyl is reduced to hydroxyl, and then the hydroxyl reacts with n-propylamine to prepare draxxin, so that the harsh reaction condition during the carbonyl epoxidation process is avoided. According to the preparation method of draxxin, the temperature range during the epoxidation reaction process is controlled to be from the room temperature to 80 DEG C, the reaction is fast, the operating time is shortened by 15% or above, the comprehensive yield is increased by 5% or above, the operation is simple and convenient, and the enlarged production is facilitated.
Patent•
19 Aug 2015
TL;DR: In this paper, a quaternary phosphonium salt compound and a preparation method for its use in the catalysis of asymmetric Mannich reaction, Michael reaction and Henry reaction are described.
Abstract: The present invention discloses a quaternary phosphonium salt compound and a preparation method thereof. The method uses cheap and readily available L-tartaric acid as the raw material, and conducts carboxyl esterification, hydroxyl protection, Grignard reaction, azide substitution, azide reduction and final reaction with phosphorus pentachloride, so as to obtain the quaternary phosphonium salt compound. The quaternary phosphonium salt compound is a novel Bronsted acid catalyst (a hydrogen bond donor catalyst), and can be used in the catalysis of asymmetric Mannich reaction, Michael reaction and Henry reaction.
Patent•
18 Nov 2015
TL;DR: In this paper, a chiral phosphazene catalyst based on a spiro framework adopting chiral diamine, a preparation method and an application of the chiral PHZene catalyst was provided.
Abstract: The invention provides a chiral phosphazene catalyst based on a spiro framework adopting chiral diamine, a preparation method and an application of the chiral phosphazene catalyst. The catalyst has a structure represented in the general formula: (RX-)3P=NR', chiral groups are introduced through R and R', and the catalyst has a structure with two seven-membered rings in centered connection through phosphorspirol. Optically pure tartaric acid or substituted hexahydrophthalic acid or 1,2-cyclopentanedicarboxylicacid,(1R,2S)-rel- is taken as a raw material, chiral diamine is generated through esterification, a Grignard reaction, an optional chlorination reaction, an azido reaction and a reduction reaction of the raw material, then chiral diamine and phosphorus pentachloride have a spirocyclization reaction to construct a phosphorspirol-centered screw ring, the chiral phosphazene molecular catalyst is obtained under the alkaline condition, and a method for substituting azido for hydroxyl directly has good application and popularization value. The catalyst has the advantages of high catalysis efficiency, good stereoselectivity, mild conditions, economy, environmental protection, simplicity and convenience in operation and the like as well as popularization and application prospects.
TL;DR: In this paper, Optically active 4-substituted γ-lactones (3 and 4) were synthesized effectively using lipase-catalyzed optical resolution.
Abstract: Abstract Optically active 4-substituted γ-lactones (3 and 4) were synthesized effectively using lipase-catalyzed optical resolution. N-methyl-4-hydroxyalkanamides (rac-1a–i) as substrates were prepared from N-methylsuccinimide. The alkylation of N-methylsuccinimide using Grignard reagents generated from various alkyl halides followed by reduction resulted in N-methyl-4-hydroxyalkanamides. The optical resolution of rac-1a–g was performed using Novozym 435-catalyzed stereoselective acetylation. The stereoselective preparation of 4-substituted γ-lactones (3 and 4) possessing various side chains such as isopentyl, phenyl, and phenethyl groups was achieved with more than 90% enantiopurity.
Patent•
07 Jan 2015
TL;DR: In this article, a brush-type difluoro monomer and a synthetic method of synthesizing it is described. But the method is limited to 3,5-dimethyl bromobenzene as a raw material.
Abstract: The invention discloses a brush-type difluoro monomer and a synthetic method thereof. The structure formula of the monomer is as shown in the specification, wherein X represents CH3 or OCH3; and n is an integer of 1-3. The monomer is prepared through Grignard reaction, nucleophilic addition reaction, bromination reaction and coupled reaction with 3,5-dimethyl bromobenzene as a raw material. The brush-type difluoro monomer contains polymerizable difluoro group and functionalized methyl or methoxy group, quaternization or sulfonated polymer can be obtained after polycondensation reaction and functional group conversion of the brush-type difluoro monomer, and the functionalized polymer can be used as a fuel cell polymer electrolyte membrane material.
TL;DR: Symmetrical spiro-1,3-bisketone (IV) is synthesized by ring-closure metathesis reaction of tetraene (I) obtained by Grignard reaction of a dialkenyl compound and allylmagnesium bromide as discussed by the authors.
Patent•
06 May 2015
TL;DR: In this paper, a preparation method of estra-4,9-diene-3,17-diketone was presented, using grignard reaction, oxidizing and ring closing reaction and hydrolyzing and ring-closing reaction according to a reaction route.
Abstract: The invention discloses a preparation method of estra-4,9-diene-3,17-diketone. The preparation method uses a compound I as a raw material and prepares the estra-4,9-diene-3,17-diketone by grignard reaction, oxidizing and ring-closing reaction and hydrolyzing and ring-closing reaction according to a reaction route shown in the figure. The preparation method has relatively cheap starting materials, high product yield and reduced cost of production.