- Continuous Flow Chlorination of Alkenyl Iodides Promoted by Copper Tubing
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A simple continuous flow synthesis of alkenyl chlorides from the corresponding readily available alkenyl iodides in copper reactor tubing is described. A variety of alkenyl chlorides were obtained in good to excellent yields with full retention of the dou
- Nitelet, Antoine,Kairouz, Vanessa,Lebel, Hélène,Charette, André B.,Evano, Gwilherm
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p. 251 - 257
(2019/01/04)
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- Transition metal free large-scale synthesis of aromatic vinyl chlorides from aromatic vinyl carboxylic acids using bleach
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While continuing our research on Hunsdiecker reaction, we came across an interesting application of bleach, sodium hypochlorite (NaOCl) for decarboxylative chlorination reaction. The reaction is easily scaled up to 10 mmol. The reaction has good tolerance towards wide variety of functional groups. The reaction has mild conditions and gave relatively high chemical yield of the desired product.
- Hatvate, Navnath T.,Takale, Balaram S.,Ghodse, Shrikant M.,Telvekar, Vikas N.
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supporting information
p. 3892 - 3894
(2018/10/02)
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- Kinetically controlled E-selective catalytic olefin metathesis
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A major shortcoming in olefin metathesis, a chemical process that is central to research in several branches of chemistry, is the lack of efficient methods that kinetically favor E isomers in the product distribution. Here we show that kinetically E-selective cross-metathesis reactions may be designed to generate thermodynamically disfavored alkenyl chlorides and fluorides in high yield and with exceptional stereoselectivity.With 1.0 to 5.0 mole % of a molybdenum-based catalyst, which may be delivered in the form of air- and moisture-stable paraffin pellets, reactions typically proceed to completion within 4 hours at ambient temperature. Many isomerically pure E-alkenyl chlorides, applicable to catalytic cross-coupling transformations and found in biologically active entities, thus become easily and directly accessible. Similarly, E-alkenyl fluorides can be synthesized from simpler compounds or more complex molecules.
- Nguyen, Thach T.,Koh, Ming Joo,Shen, Xiao,Romiti, Filippo,Schrock, Richard R.,Hoveyda, Amir H.
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p. 569 - 575
(2016/05/24)
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- METATHESIS CATALYSTS AND METHODS THEREOF
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The present application provides, among other things, compounds and methods for metathesis reactions. In some embodiments, the present disclosure provides methods for preparing alkenyl halide with regioselectivity and/or stereoselectivity. In some embodim
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Paragraph 00338
(2016/08/10)
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- A General Copper-Catalyzed Vinylic Halogen Exchange Reaction
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An efficient and general system for the halogen exchange reaction in alkenyl halides has been developed. Upon reaction with catalytic amounts of copper iodide and trans-N,N′-dimethylcyclohexane-1,2-diamine in the presence of tetramethylammonium chloride or bromide, a wide range of easily accessible alkenyl iodides can be smoothly transformed to their far less available chlorinated and brominated derivatives in excellent yields and with full retention of the double bond geometry. This reaction also enables the chlorination of bromoalkenes and could be extended to the use of gem-dibromoalkenes.
- Nitelet, Antoine,Evano, Gwilherm
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supporting information
p. 1904 - 1907
(2016/05/19)
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- Development of a general copper-catalyzed vinylic Finkelstein reaction—application to the synthesis of the C1–C9 fragment of laingolide B
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An efficient and broadly applicable procedure for the copper-catalyzed vinylic Finkelstein reaction is reported. Using a simple, readily available and cheap catalytic system, a broad range of alkenyl iodides and bromides can be smoothly converted to their lower homologues with high yields and full retention of the double bond geometry. Key features of this vinylic Finkelstein reaction are its broad applicability, enabling the conversion of readily available alkenyl iodides to their less available brominated and chlorinated counterparts, and the mild reaction conditions compatible with a range of highly functionalized substrates. The potential of this vinylic halogen exchange reaction in total synthesis and medicinal chemistry was demonstrated by its successful use for the synthesis of the C1–C9 fragment of laingolide B and for the late-stage modification of drug-like molecules. The extension of this halogen exchange to the acetylenic and allenic Finkelstein reactions is also reported.
- Nitelet, Antoine,Jouvin, Kévin,Evano, Gwilherm
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p. 5972 - 5987
(2016/09/16)
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- A green hunsdiecker reaction of cinnamic acids
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Tribromo- and trichloroisocyanuric acids react with cinnamic acids in NaOH/H2O/Et2O at room temperature to produce (E)-2-halostyrenes regioselectively in 25-95percent yield. Mechanism studies using Hammett correlations and DFT (density functional theory) calculations have shown that this reaction has as rate determining step the electrophilic addition of chlorine atom to the double bond.
- Sodre?, Leonardo R.,Esteves, Pierre M.,De Mattos, Marcio C. S.
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p. 212 - 218
(2013/05/08)
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- Catalytic olefination. Estimation of the reactivity of polyhaloalkanes
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Global electrophilicity indices and carbon-halogen bond energies of a wide series of halogen derivatives were calculated in terms of the density functional theory (DFT). The calculated values were used to estimate the reactivity of halogen derivatives under conditions of catalytic olefination. Reactions of N-unsubstituted hydrazones with polyhaloalkanes in the presence of CuCl afforded substituted alkenes. The relation between the structure of polyhaloalkanes and their reactivity was studied using the reaction with 4-chlorobenzaldehyde hydrazone as an example. It was found that increase in the global electrophilicity index and decrease in the C-Hlg bond energy are accompanied by increase in the olefinating power of halogen derivatives.
- Nenaidenko,Korotchenko,Shastin,Tyurin,Balenkova
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p. 1750 - 1756
(2007/10/03)
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- Reaction of Catalytic Olefination of Hydrazones with Polyhaloalkanes. Investigation of Alkene Formation Chemoselectivity
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Hydrazones of carbonyl compounds at treatment with polyhaloalkanes in the presence of CuCl as catalyst are converted into substituted alkenes with formation of a new C=C bond.
- Korotchenko,Shastin,Nenaidenko,Balenkova
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p. 527 - 531
(2007/10/03)
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- Catalytic olefination reaction of carbonyl compounds. A study on stereoselectivity of alkene formation
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The mechanism of formation of alkene stereoisomers in the catalytic olefination reaction of carbonyl compounds was studied. 4-Chlorobenzaldehyde hydrazone 1 stereoselectively reacts with a number of F-, Cl-, Br-, and I-containing polyhaloalkanes in the presence of catalytic amounts of CuCl to give ω-substituted styrenes 2 with the more thermodynamically stable alkene isomer being the major product. A model for the formation of the stereoisomers of alkenes 2 in the olefination reaction is proposed. Stereoselectivity of the reaction is determined by elimination of copper(II) halides from the lowest-lying conformers of organocopper intermediates II. According to quantum-chemical calculations, the elimination should involve the staggered conformations with antiperiplanar arrangement of C-Hal and C-Cu bonds and proceed by the E2 anti-elimination mechanism. The results of quantum-chemical calculations are in good agreement with the experimental E/Z alkene isomer ratios.
- Nenaidenko,Korotchenko,Shast,Tyur,Balenkova
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p. 1835 - 1840
(2007/10/03)
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- Halodecarboxylation of a,β-unsaturated carboxylic acids bearing aryl and styrenyl group at β-carbon with Oxone and sodium halide
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Reaction of α,β-unsaturated carboxylic acid bearing aryl and styrenyl group at β-carbon with Oxone and sodium halide in aqueous acetonitrile afforded the corresponding haloalkenes.
- You,Lee
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p. 105 - 107
(2007/10/03)
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- Oxidative Halo-Decarboxylation of α,β-Unsaturated Carboxylic Acids
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A procedure for oxidative halo-decarboxylation of α,β-unsaturated carboxylic acids using iodosylbenzene, or iodosylbenzene diacetate, and N-chloro-, N-bromo-, or N-iodosuccinimide is presented.Good yields of the corresponding bromoalkenes are obtained when the α,β-unsaturated carboxylic acids are substituted with an aromatic substituent in the β-position and N-bromosuccinimide is used as the halogenation reagent.The scope of mainly the oxidative bromo-decarboxylation reaction is presented, and a tentative mechanism is proposed.
- Graven, Anette,Joergensen, Karl Anker,Dahl, Soeren,Stanczak, Andrzej
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p. 3543 - 3546
(2007/10/02)
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- Synthesis of 3-Substituted Indolizines from the Reaction of Chlorocarbenes with 2-Vinylpyridine
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3-Substituted indolizines have been obtained in a one-step procedure from the reaction of chlorocarbenes with 2-vinylpyridine.
- Bonneau, Roland,Romashin, Yuri N.,Liu, Michael T. H.,MacPherson, Spenser E.
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p. 509 - 510
(2007/10/02)
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- Laser flash photolysis study of substituent effects on the rate of 1,2-H migration in a series of benzylchlorocarbenes
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Laser flash photolysis of para-substituted 3-chloro-3-benzyldiazirines in isooctane produces the corresponding carbenes, which react with pyridine to form ylides or undergo 1,2-H migration to form the (Z)- and (E)-β-chlorostyrenes. The rate for the 1,2-H migration is determined by plotting the pseudo-first-order rate constants for the growth of the ylide vs [pyridine] and extrapolating to zero pyridine concentration. In the case of (p-chlorobenzyl)chlorocarbene, the carbene decay can be monitored directly at 310 nm, whereas in [p-(trifluoromethyl)benzyl]chlorocarbene, the 285-nm trace may be analyzed as the sum of the absorption of the carbene and of the product β-chlorostyrenes. A Hammett plot of the logarithms of the rate constants for 1,2-H migration vs σp values gave a ρ value of -1.0, consistent with a hydride-like 1,2-H shift to the carbene center. The rate constants for the cyclopropanation of carbenes with tetramethylethylene (TME) were determined. In particular, the cyclopropanation of (p-chlorobenzyl)chlorocarbene with TME gave a negative activation energy of -4.7 kcal mol-1.
- Liu, Michael T. H.,Bonneau, Roland
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p. 3604 - 3607
(2007/10/02)
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- Thermolysis and Photolysis of 3-Chloro-3-benzyldiazirines in Alkenes: Evidence for a Carbene-Alkene Complex
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Photolysis and thermolysis of substituted 3-chloro-3-benzyldiazirines in alkenes yielded cyclopropanes and chlorostyrenes as products.The results suggest that the cyclopropanation of benzylchlorocarbenes is independent of substituents.However, 1,2-hydrogen migration is accelerated by OCH3 or CH3 substituents, and is decelerated by a Cl substituent on the phenyl ring.These results support the existence of an energy barrier to 1,2-H migration.Evidence is provided for carbene-alkene complexation.
- Liu, Michael T. H.,Soundararajan, N.,Paike, N.,Subramanian, R.
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p. 4223 - 4227
(2007/10/02)
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- INVESTIGATIONS ON REACTIONS OF CHLORINE DIOXIDE AND SODIUM CHLORITE WITH ORGANIC COMPOUNDS. PART XXXV. REACTIONS OF CHLORINE DIOXIDE WITH RING-SUBSTITUTED STYRENES
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Reactions of chlorine dioxide with ring substituted styrenes (1a-n) in carbon tetrachloride at 52-54 deg C were studied.The reaction products were isolated and characterised.It has been found that methyl-, chloro-, nitrostyrenes and 4-methoxystyrene are attacked by chlorine dioxide exclusively on the vinyl group, to yield the corresponding α-chloroacetophenones (2), diastereoisomers of β-chlorostyrene (6,7), oxidation products (8,9) and some polymers.Oxidation of its phenolic hydroxyl groups and vinyl polymerization took place in hydroxystyrenes.
- Kwiecien, Halina,Jalowiczor, Jozef
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p. 811 - 824
(2007/10/02)
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- Substituent and Temperature Effects on the Reactions of Benzylchlorocarbene with Alcohol
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The insertion reaction of the para-substituted benzylchlorocarbenes with methanol shows a second-order dependence in methanol, but only a first-order dependence in ethylene glycol.The results are consistent with a mechanism whereby the carbene inserts into the O-H bond of the alcohol dimer or oligomer by electrophilic attack of the carbene on the oxigenone pair to produce a reversibly formed ylide intermediate.The effects of the substituents indicate that electron-releasing group favours rearrangement while electron-withdrawing group facilitates insertion.Photolysis of halogenodiazirines in methanol at low temperatures give rise to V-shaped Arrhenius behaviour and the importance of N2 in influencing the reactivity of the singlet halogenocarbene in the matrix is demonstrated.
- Liu, Michael T. H.,Subramanian, Ramasamy
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p. 1233 - 1240
(2007/10/02)
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- CARBON-CARBON BOND FORMING REACTION OF BIS(CHLOROMETHYL)SULFONE WITH CARBONYL COMPOUNDS: GENERAL ROUTE TO AROMATIC 2-CHLOROVINYL COMPOUNDS AND α-HYDROXYALDEHYDES
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Bis(chloromethyl)sulfone (1) has been proved to be a useful reagent for the synthesis of aromatic 2-chlorovinyl compounds (4) from aromatic aldehydes and of α-hydroxyaldehydes (5) from aliphatic carbonyl compounds with one carbon prolongation.The sec-butyllithium-aided reaction of 1 with aromatic aldehydes gives 1,3-oxathiolane-3,3-dioxides (2) which are converted to 4 in good yields by thermolysis.On the other hand, the sodium hydride-aided reaction of 1 with aliphatic carbonyl compounds is favorable to the formation of chloromethylsulfonyloxiranes (3).Titanium tetrachloride has been found to be an efficient reagent for hydrolysis of 3 to 5.
- Nagashima, Enkou,Suzuki, Kunio,Ishikawa, Motoaki,Sekiya, Minoru
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p. 1873 - 1879
(2007/10/02)
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- TEMPERATURE AND MATRIX EFFECTS ON COMPETITIVE INTERMOLECULAR AND INTRAMOLECULAR REACTION OF BENZYLCHLOROCARBENES IN ETHANOL
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Benzylchlorocarbenes generated photolytically from diazirines in EtOH afford chlorostyrenes and acetals, whose distributions are sensitive to the reaction temperature.
- Tomioka, Hideo,Hayashi, Norihiro,Izawa, Yasuji,Liu, Michael T. H.
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p. 4413 - 4416
(2007/10/02)
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- Photolysis of 3-Chlorodiazirine in the Presence of Alkenes: Orientational Factors in the Intermolecular Interception of Chlorocarbene by Alkenes
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The stereochemistry of the 1,2-H shift of photolytically generated benzylchlorocarbene is significantly affected by aryl substituents and by the addition of an alkene.
- Tomioka, Hideo,Hayashi, Norihiro,Izawa, Yasuji,Liu, Michael T. H.
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p. 476 - 478
(2007/10/02)
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