Ethyl Iodoacetate Research Articles

Catalytic Enantioselective Reformatsky Reaction with ortho-Substituted Diarylketones

The catalytic enantioselective Reformatsky reaction with ortho-substituted diarylketones with good enantioselectivities and moderate to good yields is reported. A readily available BINOL derivative is used as a chiral catalyst, and the reactions are performed with ethyl iodoacetate as a nucleophile and Me2Zn as the zinc source. The presence of air was found to be crucial to achieve an effective C-C bond formation pointing to a radical mechanism.

ChemInform Abstract: Dimethylzinc‐Mediated, Oxidatively Promoted Reformatsky Reaction of Ethyl Iodoacetate with Aldehydes and Ketones.

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Dimethylzinc‐Mediated, Oxidatively Promoted Reformatsky Reaction of Ethyl Iodoacetate with Aldehydes and Ketones

AbstractA practical and general Reformatsky reaction, promoted by oxidants and mediated by dimethylzinc, is described. The reaction is fast and runs at 0 °C with aldehydes and ketones, under mild reaction conditions. Preliminary results obtained for the enantioselective version show that inexpensive chiral amino alcohols could be used in the challenging formation of enantioenriched quaternary stereogenic centers.

Radical reactions initiated by the photochemical cleavage of carbon–indium bonds of organoindium compounds

Intra- and intermolecular reactions of carbon-centered radicals generated by photolysis of organoindium compounds were examined. The photolysis of vinylindium compounds and indium acetylides provided vinyl and alkynyl radicals, respectively, which were trapped with ethyl iodoacetate giving the corresponding β,γ-unsaturated esters. Allylic indium compounds, prepared from 8-bromo- or 8-iodooct-1,6-dienes and powdered indium metal, underwent an intramolecular radical cyclization to afford the 5- exo- trig product.

A Catalytic Enantioselective Imino‐Reformatsky Reaction

AbstractThe admission of air in the reaction mixture of imine, ethyl iodoacetate and dimethylzinc, in the presence of 20–30 mol % of inexpensive and commercially available N‐methylephedrine as the chiral ligand, promoted the Reformatsky reaction, without the need for other metals or catalysts. Excellent yields (up to 92 %) and enantioselectivities (83–94 %) were obtained for the tested substrates. The reaction shows a broad scope, and all the imines are prepared in situ, using Me2Zn as the dehydrating agent.

Controlled copolymerization of vinyl acetate with 1‐alkenes and their fluoro derivatives by degenerative transfer

AbstractThe degenerative transfer copolymerization of vinyl acetate with ethene and higher 1‐alkenes, as well as their fluoro derivatives (RfCHCH2), under mild conditions was carried out using AIBN as the initiator and ethyl iodoacetate as the control agent. The obtained random copolymers were fairly high in alkene content, with high molecular weights and relatively narrow polydispersities. The quasi‐living nature of the copolymerization allowed the synthesis of a block terpolymer by sequential addition of two different 1‐alkene comonomers to a vinyl acetate copolymerization system. The fluorinated side chains of vinyl acetate/fluoro alkene copolymers segregate toward the air‐side of thin films, resulting in advancing water contact angle as high as 114°. 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3728–3736, 2005

The Reaction of Triphenylarsine Oxide with Ethyl Iodo‐acetate Leading to Triphenyl (Carboethoxy)methylarsonium Triiodide.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Addition of Electrophilic and Heterocyclic Carbon‐Centered Radicals to Glyoxylic Oxime Ethers.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Addition of electrophilic and heterocyclic carbon-centered radicals to glyoxylic oxime ethers.

[reaction: see text] Stabilized primary radicals can be formed from alkyl halides in an atom transfer process with Et(3)B. This process depends on the strength of the carbon-halogen bond and the stability of the resulting primary radical. Radicals formed from benzyl iodide and ethyl iodoacetate add to glyoxylic oxime ethers; however, more electrophilic radicals do not. Glyoxylic oxime ethers are also good radical acceptors for heterocyclic carbon-centered secondary radicals, giving novel alpha-amino acid derivatives.

The reaction of triphenylarsine oxide with ethyl iodo‐acetate leading to triphenyl (carboethoxy)methylarsonium triiodide

AbstractNew data are presented for some processes accompaning “retro‐Arbuzov” reaction of tertiary arsine oxides with halogen‐containing reagents. Triphenyl (carboethoxy)methylarsonium triiodide 10a was obtained in the reaction of triphenylarsine oxide 1a with excess of ethyl iodoacetate 2a. The structure of 10a was established by X‐ray single crystal diffraction. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:482–485, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20050

Controlled/Living Radical Polymerization of Vinyl Acetate by Degenerative Transfer with Alkyl Iodides

Controlled/living radical polymerization of vinyl acetate was achieved by a degenerative transfer process using alkyl iodides as transfer agents. Poly(vinyl acetate) with predetermined molecular weight and relatively low polydispersity was successfully synthesized. Methyl 2-iodopropionate and ethyl iodoacetate were employed as transfer agents, whereas 2,2‘-azobis(isobutyronitrile) and α-cumyl peroxyneodecanoate were used as initiators. Methyl 2-iodopropionate and ethyl iodoacetate are both efficient transfer agents, yielding polymers with good agreement between theoretical and observed molecular weights up to Mn = 20 000 and low polydispersities (Mw/Mn < 1.5). In contrast, ethyl iodide was inefficient as a transfer agent, although it retarded polymerization. The influence of temperature and the concentrations of transfer agent and initiator were studied. The structure of poly(vinyl acetate) end groups was investigated using 1H NMR. The iodo-terminated chain ends were unstable and decomposed to aldehyde mo...

Synthetic approaches to homochiral bicyclo[5.2.1]decanes based on d-camphor

The Reformatsky reaction of bornanic enone (10-nor-1-vinylcamphor) with ethyl iodoacetate followed by iodocyclization afforded tricyclic iodolactone. Fragmentation of the latter initiated by HgO—I2 gave rise to bicyclic iodoxolactone. Attempts to perform cyclization of this iodoxolactone analogously to intramolecular alkylation of CH-acids with halogen-containing electrophiles failed.

Direct Evidence of a Radical Mechanism in the Addition Reaction of Iododifluoroesters to Olefins by Spin Trapping

We present EPR analysis of the reaction of ethyl iododifluoroacetate with 1-tetradecene in the presence of Zn + NiCl2 x 6H2O, confirming the mechanistic studies that provide evidence of a single electron transfer process. We have trapped for the first time the ethoxycarbonyldifluoromethyl radical with a variety of spin traps, such as phenyl tert-butyl nitrone (PBN), 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), 2-methyl-2-nitrosopropane (MNP), and 2-nitro-2-nitrosopropane (NNP), and the EPR spectra of the corresponding adducts have been recorded. In a second step the ethoxycarbonyldifluoromethyl radical adds to the olefin to furnish a second radical intermediate, which can be trapped with NNP. Evidence of this second radical was obtained by EPR only with electron-rich olefins, such as alpha-methylstyrene and 2,4,6-trimethylstyrene, and the new adducts were recorded and interpreted. In addition, we also report the EPR spectra of the corresponding adducts when other alkylating reagents are used, such as ethyl iodoacetate, n-perfluorohexyl iodide, methyl omega-iodohexadecanoate, and n-butyl iodide.

The Palladium-Catalyzed Reaction ofo-Alkynyltrifluoroacetanilides with Alkyl Halides. An Entry into 2-Substituted 3-Alkylindoles

Indolylcarboxylate esters 2 and 2-substituted 3-benzylindoles 4 are prepared usually in good yield through the palladium-catalyzed reaction of o-alkynyltrifluoro acetanilides with ethyl iodoacetate or benzyl bromide. Best results are obtained by employing Pd2(dba)3 and tris(2,4,6-trimethoxyphenyl)phosphine in THF.

Functional transformation of aldehydes and ketones via homolytic induced decomposition of unsaturated peroxy acetals and peroxy ketals

Induced decomposition of unsaturated peroxy acetals prepared from trimethyl orthoformate, dodecanal or 2-methylundecanal and 2,3-dimethyl-2-hydroperoxybut-3-ene, in the presence of ethyl iodoacetate, CCl4 or dodecanethiol, allowed respectively their iodo-, chloro- and hydro- decarbonylation with yields of over 70%; the same reaction applied to the monoperoxy ketal or diperoxy ketal of cyclohexanone in the presence of ethyl iodoacetate resulted in its functional transformation in methyl 6-iodohexanoate or 1,5-diiodopentane with respective yields of 65 and 40%.

η2-Alkynyl and Vinylidene Transition Metal Complexes. 5.1 Reaction of the Metal−Acetylide [(η5-C5H5)(CO)(NO)WC⋮CR]- with Ethyl Iodoacetate as Electrophile. Preparation and Crystal Structure Analysis of a Metallacyclic Complex

Treatment of η1-acetylide complexes [(η5-C5H5)(CO)(NO)WC⋮CR]- (R = C(CH3)3 (2a), C6H5 (2b), p-CH3C6H4 (2c)) with ethyl iodoacetate in THF at −78 °C afforded, after protonation with diluted acids, the corresponding oxametallacyclopentadienyl complexes (η5-C5H5)W(I)(NO)[η2-OC(CH2COOC2H5)CHCR] (3a−c). The formation of these metallafuran derivatives is rationalized by the electrophilic attack of ethyl iodoacetate on the metal center of 2 to create first [(η5-C5H5)(I)(CO)(NO)WC⋮CR]. Subsequent nucleophilic addition of the ester enolate anion of [CH2COOC2H5]Li and a reductive-elimination step followed by protonation lead to the product 3. One of the reaction intermediates was trapped by the addition of CF3SO3CH3.

A Unified Strategy for the Stereocontrolled Construction of Structurally Unusual Sesquiterpene Lactones. Asymmetric Synthesis of Vulgarolide and Deoxocrispolide

The bicyclic ketone (+)-17b reacts with vinylmagnesium bromide from its exo face, thus enabling exploitation of the anionic oxy-Cope rearrangement and direct alkylation of the enolate so formed with ethyl iodoacetate to provide 24 in an efficient, stereocontrolled manner. Tricyclic lactone 26b, readily produced from 24, proved to be a common precursor to both synthetic targets. The construction of vulgarolide (9) proceeded by transforming the SEM group in 26b into a mesylate for the purpose of conversion to epoxy acid 39 in advance of oxidative cleavage of the double bond. This transformation resulted in direct conversion to 9 and its epimer 42. Central to the companion synthesis of deoxocrispolide (4) was the ability of 37 to undergo the Michael addition of methoxide ion and of 54 to experience regiocontrolled dehydration to bridgehead olefin 55 in a protocol that involves the smooth translocation of bridgehead unsaturation with concomitant functionalization as an allylic alcohol.

Kinetics of the reaction of chromium (II) with ethyliodoacetate, iodoacetatopentaamminecobalt (III)

The kinetics and products of the reaction of aqueous chromium ( II) with ethyliodoacetate (EIA) and (NH 3) 5CoO 2CCH 2I 2+ have been studied in 1.0 M LiClO 4/HClO 4, with rate constants reported at 25° C. All these reactions are first order in [Cr 2+] and independent of [H +]. The iodine atom abstraction from ethyliodoacetate by chromium(II) gives rate = k [ Cr 2+] [ EIA], k = 0.41 ±0.02 M −1 s −1, ΔH ∗ = 20.4 ± 5 kJ mol −1, ΔHS ∗ = - 184 ± 14 J mol − K −1 . The reaction of (NH 3) 5CoO 2CCH 2I 2+ is complicated because of competing iodine atom abstration and cobalt(III) reduction and the reaction is biphasic. The overall rate for the first stage gives k 1 app = 0.23 ± 0.02 M −1 s −1, ΔHH ∗ = 22.0 ± 7.2 kJ mol −1, ΔHS ∗ = - 183 ± 20.6 J mol −1 K −1 . The contributions have been separated by a study of the rate of cobalt(II) production. The first stage yields (NH 3) 5CoO 2CCH 2−Cr(OH 2) 5 4+ (B 1)( k = 0.07 M −1 s −1) and (H 2O) 5CrO 2CCH 2I 2+ (A 1) ( k = 0.13 M −1 s −1). For the second stage, k 2 aap = 0.053 ± 0.004 M −1 s −1, ΔH ∗ = 195 ± 5.0 kJ mol −1, ΔS ∗ = −204 ± 13.4 cal mol −1 K −1 and this stage involves halogen abstraction from A 1 ( k = 0.045 M −1s −1) and cobalt(III) reduction of B 1 ( k − 0.012 M −1 s −1). The aquation of (H 2O) 5CrI 2+ catalysed by Cr(II) has been observed as a second stage in the reaction of EIA, and an independent study gives the following kinetic results: rate = k[ Cr 2+][( H 2 O) 5 CrI 2+]/[ H +], k = 0.020 ± 0.002 s −1, ΔH ∗ = 69.9 ± 3.0 kJ mol ΔS ∗ = −42.7 ± 13.7 J mol −1 K −1 . A rate constant correlation for this pathway for a number of complexes is suggested.

A New Short Synthesis of (±)-Eburnamonine

A new short synthesis of the indole alkaloid eburnamonine (1), starting from the easily available enamine (3) (1,12b-didehydroindolo[2,3-a]quinolizidine) is described. Pentacyclic lactam (7) (18-nor-19- ethoxycarbonyl-21-epieburnamonine) (trans D/E ring juncture), the key intermediate in this synthesis, was prepared from enamine (3) by dialkylating with ethyl iodoacetate in the presence of diisopropylethylamine (DIPEA). LiAlH 4 -reduction of lactam (7) gave a 2:1 mixture of compounds (10a) (21-epi-18-hydroxyeburnamine) and (10b) (16-epi-21-epi-18-hydroxyeburnamine)

General synthesis of homochiral trisubstituted γ-butyrolactones

The synthetically useful keto ester methyl 2-deoxy-2-(2-ethoxy-2-oxoethyl)-4,6-O-(phenylmethylene)-α-D-ribo-hexopyranosid-3-ulose can be prepared exclusively by reaction of the potassium enolate of methyl 2-deoxy-4,5-O-(phenylmethylene)-α-D-erythro-hexopyranosid-3-ulose and ethyl iodoacetate in toluene in 74% yield. Reduction of methyl 2-deoxy-2-(2-ethoxy-2-oxoethyl)-4,6-O-(phenylmethylene)-α-D-ribo-hexopyranosid-3-ulose and subsequent cyclisation led to methyl 2-deoxy-2-(2-oxoethyl)-4,6-O-(phenylmethylene)-α-D-allopyranoside 2′,3 lactone, whose lithium enolate reacted with high stereoselectivity to give exclusively (>95% d.r.) methyl 5′-(R)-2-deoxy-5′-methyl-2-(2-oxoethyl)-4,6-O-(phenylmethylene)-α-D-allopyranoside 2′,3 lactone, methyl 5′-(R)-2-deoxy-5′-(1-hexyl)-2-(2-oxoethyl)-4,6-O-(phenylmethylene)-α-D-allopyranoside 2′,3 lactone and methyl 5′-(R)-2-deoxy-2-(2-oxoethyl)-4,6-O-(phenylmethylene)-5′-(2-propenyl)-α-D-allopyranos-ide 2′,3 lactone derivatives. This method provides a convenient and high-yielding route to homo-chiral γ-butyrolactones, thereby offering an opening into a wide range of enantiomerically pure γ-lactones. The work described provides another solution to the ‘off-template’ problem.