Showing papers on "Grignard reaction published in 2014"
TL;DR: A 4-substituted-1-tosyl-1,2,3-triazole-based stereoselective synthesis of structurally diverse oxaspirocycles is reported, and has been successfully applied to the total syntheses of (±)-tuberostemospiroline and (±-stemona-lactam R.
Abstract: A 4-substituted-1-tosyl-1,2,3-triazole-based stereoselective synthesis of structurally diverse oxaspirocycles is reported. The synthesis involves Rh-catalyzed loss of nitrogen from 4-substituted-1-tosyl-1,2,3-triazoles, Grignard reaction, and a ring-closing metathesis reaction as key steps. By employing readily available and stable 4-substituted-1-tosyl-1,2,3-triazoles as surrogates of diazo compounds and nitrogen sources, two types of oxaspirocycles were obtained. The latter compounds, which contain adjacent nitrogen stereocenters, could serve as the core structures of many natural products. This chemistry has been successfully applied to the total syntheses of (±)-tuberostemospiroline and (±)-stemona-lactam R.
51 citations
TL;DR: In the presence of excess PhMgBr, [Fe(III)(acac)3] affords two reduced complexes that react with the aryl or heteroaryl halides and react with each other through an oxidative addition/reductive elimination sequence.
Abstract: The mechanism of the reactions of aryl/heteroaryl halides with aryl Grignard reagents catalyzed by [Fe(III)(acac)3] (acac=acetylacetonate) has been investigated. It is shown that in the presence of excess PhMgBr, [Fe(III)(acac)3] affords two reduced complexes: [PhFe(II)(acac)(thf)n] (n=1 or 2) (characterized by (1)H NMR and cyclic voltammetry) and [PhFe(I)(acac)(thf)](-) (characterized by cyclic voltammetry, (1)H NMR, EPR and DFT). Whereas [PhFe(II)(acac)(thf)n] does not react with any of the investigated aryl or heteroaryl halides, the Fe(I) complex [PhFe(I)(acac)(thf)](-) reacts with ArX (Ar=Ph, 4-tolyl; X=I, Br) through an inner-sphere monoelectronic reduction (promoted by halogen bonding) to afford the corresponding arene ArH together with the Grignard homocoupling product PhPh. In contrast, [PhFe(I)(acac)(thf)](-) reacts with a heteroaryl chloride (2-chloropyridine) to afford the cross-coupling product (2-phenylpyridine) through an oxidative addition/reductive elimination sequence. The mechanism of the reaction of [PhFe(I)(acac)(thf)](-) with the aryl and heteroaryl halides has been explored on the basis of DFT calculations.
50 citations
TL;DR: It was reported for the first time that hot water as a mildly acidic catalyst efficiently promoted 1,n-rearrangement of allylic alcohols and joined isolated C-C double or triple bonds to generate conjugated polyene or enyne structure motifs.
Abstract: It was reported for the first time that hot water as a mildly acidic catalyst efficiently promoted 1,n-rearrangement (n = 3, 5, 7, 9) of allylic alcohols In some cases, the rearrangement reactions joined isolated C–C double or triple bonds to generate conjugated polyene or enyne structure motifs We used the 1,3-rearrangement reaction of an allylic alcohol in hot water as part of an attractive new strategy for construction of the polyene natural product navenone B by iterative use of a Grignard reaction, a 1,3-rearrangement of the resulting allylic alcohol, and subsequent oxidation of the rearranged product
37 citations
TL;DR: In this paper, a new strategy for synthesis of polystyrene-graft polythiophene (PSt-g-PTh) is explored, in which the graft copolymerization of thiophene monomers onto poly-styrene backbone was initiated by oxidized thio-thio groups after addition of ferric chloride (FeCl3), an oxidative catalyst for polythio-structure synthesis, and FeCl3-doped polystiophene was chemically grafted onto the polystructure via oxidation polymerization.
Abstract: In this paper, a new strategy for synthesis of polystyrene-graft-polythiophene (PSt-g-PTh) is explored. For this purpose, first poly(styrene-co-acrylonitrile) (PSt-co-PAN) was synthesized via atom transfer radical polymerization (ATRP), and then the nitrile groups of acrylonitrile units were converted to thiophene groups using Grignard reaction between 2-thienylmagnesium bromide and nitrile groups to produce a thiophene-functionalized polystyrene macromonomer (ThPStM). The graft copolymerization of thiophene monomers onto polystyrene backbone was initiated by oxidized thiophene groups after addition of ferric chloride (FeCl3), an oxidative catalyst for polythiophene synthesis, and FeCl3-doped polythiophene was chemically grafted onto the polystyrene backbone via oxidation polymerization. The graft copolymer obtained was characterized by 1H nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy, and its electroactivity behavior was verified under cyclic voltammetric conditions. Moreover, thermal behaviors of the synthesized polymers were investigated by means of differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA).
28 citations
TL;DR: The work presented herein establishes a set of secondary reaction strategies utilizing allyl-terminated surfaces to modify chemically protected GaP surfaces as covalent secondary functionalization of GaP(111)A interfaces.
Abstract: The functionalization of single crystalline gallium phosphide (GaP) (111)A surfaces with allyl groups has been performed using a sequential chlorine-activation/Grignard reaction process. Increased ...
20 citations
TL;DR: A-seco-triterpenoids with a methylketone group were synthesized from epimeric 3-hydroxy-3-methyl-1-cyano-2-norlup1(3),20(29)-dien-28-oate, which inhibited in vitro reproduction of human immunodeficiency virus type 1 as discussed by the authors.
Abstract: A-seco-triterpenoids with a methylketone group were synthesized from epimeric 3-hydroxy-3-methyl-1-cyano2,3-seco-triterpenoids of the lupane and 19,28-epoxy-18H-oleanane types, which were formed by a Grignard reaction. The resulting methylketones underwent under base-catalysis conditions an intramolecular cyclization to form A-pentacyclic -substituted alkenenitriles. The synthesized compounds included 3-methyl1-cyano-19,28-epoxy-2,3-seco-2-nor-18H-olean-3-one and methyl 3-methyl-1-cyano-2-norlup1(3),20(29)-dien-28-oate, which inhibited in vitro reproduction of human immunodeficiency virus type 1.
20 citations
TL;DR: N,N'-Diphenyl-p-benzoquinonediimine, a redox-active unit of polyaniline, efficiently induced the oxidative homocoupling of various aryl- and vinylmagnesium reagents in suppressing the side reactions, such as 1,2- or 1,4-addition reaction.
Abstract: N,N′-Diphenyl-p-benzoquinonediimine, a redox-active unit of polyaniline, efficiently induced the oxidative homocoupling of various aryl- and vinylmagnesium reagents in suppressing the side reactions, such as 1,2- or 1,4-addition reaction.
19 citations
TL;DR: To enhance the scope of heavy calcium-based Grignard reagents, 1,2-dihydro-4-iodonaphthalene was reduced with calcium in THF giving tetrakis(thf), which represents a 1-alkenylcalcium complex based on X-ray structure determination and NMR data.
Abstract: To enhance the scope of heavy calcium-based Grignard reagents, 1,2-dihydro-4-iodonaphthalene (1) was reduced with calcium in THF giving tetrakis(thf) (1,2-dihydronaphth-4-yl)calcium iodide (2). This derivative represents a 1-alkenylcalcium complex based on X-ray structure determination and NMR data. The stability of this compound is significantly reduced compared with the aromatic naphthylcalcium iodide.
18 citations
TL;DR: A general method for functionalizing olefins with aromatic, aliphatic, and vinyl Grignard reagents was developed and was utilized to synthesize a series of skipped dienes, a class of compounds that are prevalent in natural products and are difficult to synthesizing by known allylic alkylation methods.
Abstract: New advances in the functionalization of unactivated olefins with carbon nucleophiles have provided more efficient and practical approaches to convert inexpensive starting materials into valuable products. Recent examples have been reported with stabilized carbon nucleophiles, tethered carbon nucleophiles, diazoesters, and trifluoromethane donors. A general method for functionalizing olefins with aromatic, aliphatic, and vinyl Grignard reagents was developed. In a one-pot process, olefins are oxidized by a commercially available reagent to allylic electrophiles, which undergo selective copper-catalyzed allylic alkylation with Grignard reagents. Products are formed in high yield and with high regioselectivity. This was utilized to synthesize a series of skipped dienes, a class of compounds that are prevalent in natural products and are difficult to synthesize by known allylic alkylation methods.
18 citations
TL;DR: In this paper, conditions for fast Ni-catalyzed Kumada-type cross-coupling of functionalized benzyl and allyl chlorides with alkylmagnesium reagents were discovered.
17 citations
TL;DR: In this article, a novel ketamine derivative, 2-(2-fluorophenyl)-2-methylamino-cyclohexanone, has been called fluoroketamine by the authors.
TL;DR: An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier-Grignard reaction of unactivated alkyl or aryl bromides with ester in THF at 65°C catalyzed by CuO has been developed and systematically investigated as discussed by the authors.
TL;DR: The first total synthesis of polyketide natural product cryptosporiopsin A was described, accomplished in 12 longest linear steps with 15.4% overall yield starting from enantiomerically pure epoxide 12 prepared by hydrolytic kinetic resolution.
Abstract: The first total synthesis of polyketide natural product cryptosporiopsin A (1) was described. It has been accomplished in 12 longest linear steps with 15.4% overall yield starting from enantiomerically pure epoxide 12 prepared by hydrolytic kinetic resolution. Other key steps were Stille coupling, Grignard reaction, De Brabander's esterification and ring closing metathesis (RCM) reaction.
TL;DR: The porphyrinyl Grignard reagents are nucleophilic enough to react with various carbonyl compounds, such as aldehydes, ketones, and amides.
TL;DR: In this article, the 1,2-dianion reactivity of the reagent generated from EtMgBr and titanium isopropoxide was illustrated when N-acyl cyanohydrins were used as substrates (>20 examples), giving both aminocyclopropane derivatives and 1,4-dicarbonyl compounds.
TL;DR: In this article, a new stereoselective approach for the synthesis of AI-77-B has been described, where the chiral amino acid moiety has been obtained from d -ribose involving Grignard reaction on ribosylimine.
TL;DR: In this article, a simple synthetic methodology to cyclophanes containing hydroxyl groups has been reported, and the key steps involved here are: Grignard reaction, double Claisen rearrangement, and ring-closing metathesis.
TL;DR: In this article, the Kulinkovich cyclopropanation of esters with disubstituted homoallylic alcohols is described for the preparation of 1,2,3-trisubstitiuted cyclopanols.
TL;DR: In this paper, a convergent synthesis of C19-C27 fragment of bryostatin-11 is described, and the key steps involved in this approach are kinetic resolution, Grignard reaction, and Sharpless dihydroxylation.
TL;DR: In this paper, a concise and efficient total synthesis of honokiol, a biphenyl-type neolignan is accomplished in six steps using readily available and cost-effective reagents.
TL;DR: In this article, a highly convergent stereoselective total synthesis of stagonolide F was described starting from commercially available 5-hexen 1-ol using asymmetric dihydroxylation, Jacobsen's hydrolytic kinetic resolution (HKR), regioselectively epoxide ring opening with vinyl Grignard reaction, esterification, and ring-closing metathesis (RCM) as key steps.
TL;DR: A stereoselective approach to tricyclic core of yaoshanenolides from simple aromatic precursor is described in this article, where the Grignard reaction, alkylation, and ring-closing metathesis reaction are the key features of the approach.
TL;DR: A new and efficient route tointernal alkynes is described by Pd-catalyzed Kumada cross-coupling reactions of alkynyl halides with Grignard reagents, giving the corresponding internal alkynes in moderate to good yields.
TL;DR: In this paper, a simple and practical synthesis of (−)-lentiginosine 2 with good overall yield has been achieved from the commercially available diethyl d -tartarate.
Abstract: A simple and practical synthesis of (−)-lentiginosine 2 with good overall yield has been achieved from the commercially available diethyl d -tartarate. The key steps are a highly stereoselective Grignard reaction on an aldehyde and a Staudinger reduction.
TL;DR: The Grignard reaction is used to turn bromobenzene into benzoic acid, nucleophilic acyl substitution to transform the resulting carboxylic acid into an acid chloride, and the addition of H2O2/NaOH to the acid chloride to yield benzoyl peroxide as mentioned in this paper.
Abstract: Benzoyl peroxide is used as a bleaching agent for flour and whey processing, a polymerization initiator in the synthesis of plastics, and the active component of acne medication. Because of its simplicity and wide application, benzoyl peroxide is a target molecule of interest. It can be affordably synthesized in three steps from bromobenzene using procedures that can be performed in four, 4 h laboratory periods. This process includes a Grignard reaction to turn bromobenzene into benzoic acid, nucleophilic acyl substitution to transform the resulting carboxylic acid into an acid chloride, and the addition of H2O2/NaOH to the acid chloride to yield benzoyl peroxide. Most organic chemistry students are familiar with these traditional reaction mechanisms because they are covered in introductory organic chemistry courses. The starting materials for each reaction are commercially available, and the products can be readily characterized using NMR spectroscopy, IR spectroscopy, and melting point.
TL;DR: The first total synthesis of catenioblin B via a titanium(IV) mediated regioselective epoxide ring-opening, Grignard reaction, Luche’s reduction and TEMPO/BAIB mediated intramolecular cyclization as the key steps is reported.
TL;DR: The first total synthesis of the natural saturated α-pyrone pectinolide F has been accomplished from inexpensive, commercially available (S )-ethyl lactate and but-3-yn-1-ol.
Abstract: The first total synthesis of the natural saturated α-pyrone pectinolide F has been accomplished from inexpensive, commercially available ( S )-ethyl lactate and but-3-yn-1-ol. The salient features of the synthesis are 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO)–[bis(acetoxy)iodo]benzene oxidation, Sharpless asymmetric dihydroxylation, Grignard reaction, and partial hydrogenation of the triple bond.
TL;DR: In this paper, a stereoselective synthesis of tetrahydropyran-tetrahydrofuran (THP-THF) core 2 of (+)-muconin (1) has been achieved using Prins cyclization as a key step to construct tetrahedropyrin moiety.
Patent•
12 Feb 2014
TL;DR: In this article, a preparation method of an arylboronic acid compound is presented, where a single solvent used in reaction is replaced with a mixed solvent so that the reaction and industrial safety can be improved, and the cost of the raw material can be decreased; in addition, a simple and efficient purification method is provided.
Abstract: The invention provides a preparation method of an arylboronic acid compound and belongs to the field of organic synthesis. According to the preparation method of the arylboronic acid compound, the arylboronic acid compound is prepared from aryl halohydrocarbon by Grignard reaction and esterification hydrolysis reaction; and the prepared arylboronic acid compound is applied to a hydrocarbon sensor, nucleoside and saccharides selective transporters, an enzyme inhibitor and the like in biology, medical science or materials science. According to the preparation method, a single solvent used in reaction is replaced with a mixed solvent so that the reaction and industrial safety can be improved, and the cost of the raw material can be decreased; in addition, a simple and efficient purification method is provided; and the method is simple in preparation process, mild in reaction conditions, simple and controllable in operation, and suitable for massive industrial production.
TL;DR: In this article, a low-molecular-weight polypyrimidine in a π-conjugated main chain was prepared by a Grignard reaction between 2-amino-4,6-dichloropyrimidine and 1,4-dibromo-2,5-didodecyloxybenzene.
Abstract: A new type of low-molecular-weight polypyrimidine in a π-conjugated main chain was prepared by a Grignard reaction between 2-amino-4,6-dichloropyrimidine and 1,4-dibromo-2,5-didodecyloxybenzene in the presence of [1,2-Bis(diphenylphosphino) ethane]dichloronickel(II). The structure of the copolymer was fully elucidated by Fourier transform infrared spectroscopy, 1H-NMR, and elemental analysis. The copolymer had good solubility in common organic solvents. The copolymer displayed a bathochromic shift when protonated with an organic or inorganic acid in chloroform or tetrahydrofuran. The copolymer depicted facile p-doping and good electron-transporting electrochemical properties in a 1M H2SO4 aqueous solution. The copolymer showed a narrow polydispersity of 1.04. Thermogravimetric analysis showed that the copolymer had a certain thermal stability with no decomposition at a temperature of 250°C under N2. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41174.