- Oxidative Decarboxylase UndA Utilizes a Dinuclear Iron Cofactor
-
UndA is a nonheme iron enzyme that activates oxygen to catalyze the decarboxylation of dodecanoic acid to undecene and carbon dioxide. We report the first optical and M?ssbauer spectroscopic characterization of UndA, revealing that the enzyme harbors a coupled dinuclear iron cluster. Single turnover studies confirm that the reaction of the diferrous enzyme with dioxygen produces stoichiometric product per cluster. UndA is the first characterized example of a diiron decarboxylase, thus expanding the repertoire of reactions catalyzed by dinuclear iron enzymes.
- Manley, Olivia M.,Fan, Ruixi,Guo, Yisong,Makris, Thomas M.
-
-
Read Online
- Preparation of Primary and Secondary Dialkylmagnesiums by a Radical I/Mg-Exchange Reaction Using sBu2Mg in Toluene
-
The treatment of primary or secondary alkyl iodides with sBu2Mg in toluene (25–40 °C, 2–4 h) provided dialkylmagnesiums that underwent various reactions with aldehydes, ketones, acid chlorides or allylic bromides. 3-Substituted secondary cyclohexyl iodides led to all-cis-3-cyclohexylmagnesium reagents under these exchange conditions in a highly stereoconvergent manner. Enantiomerically enriched 3-silyloxy-substituted secondary alkyl iodides gave after an exchange reaction with sBu2Mg stereodefined dialkylmagnesiums that after quenching with various electrophiles furnished various 1,3-stereodefined products including homo-aldol products (99 % dr and 98 % ee). Mechanistic studies confirmed a radical pathway for these new iodine/magnesium-exchange reactions.
- Knochel, Paul,Lutter, Ferdinand H.,Sunagatullina, Alisa S.
-
supporting information
(2022/02/16)
-
- Unexpected Reactions of α,β-Unsaturated Fatty Acids Provide Insight into the Mechanisms of CYP152 Peroxygenases
-
CYP152 peroxygenases catalyze decarboxylation and hydroxylation of fatty acids using H2O2 as cofactor. To understand the molecular basis for the chemo- and regioselectivity of these unique P450 enzymes, we analyze the activities of three CYP152 peroxygenases (OleTJE, P450SPα, P450BSβ) towards cis- and trans-dodecenoic acids as substrate probes. The unexpected 6S-hydroxylation of the trans-isomer and 4R-hydroxylation of the cis-isomer by OleTJE, and molecular docking results suggest that the unprecedented selectivity is due to OleTJE’s preference of C2?C3 cis-configuration. In addition to the common epoxide products, undecanal is the unexpected major product of P450SPα and P450BSβ regardless of the cis/trans-configuration of substrates. The combined H218O2 tracing experiments, MD simulations, and QM/MM calculations unravel an unusual mechanism for Compound I-mediated aldehyde formation in which the active site water derived from H2O2 activation is involved in the generation of a four-membered ring lactone intermediate. These findings provide new insights into the unusual mechanisms of CYP152 peroxygenases.
- Jiang, Yuanyuan,Li, Shengying,Li, Zhong,Peng, Wei,Tang, Dandan,Wang, Binju,You, Cai,Zhao, Yue
-
supporting information
p. 24694 - 24701
(2021/10/14)
-
- Piperazine-promoted gold-catalyzed hydrogenation: The influence of capping ligands
-
Gold nanoparticles (NPs) combined with Lewis bases, such as piperazine, were found to perform selective hydrogenation reactions via the heterolytic cleavage of H2. Since gold nanoparticles can be prepared by many different methodologies and using different capping ligands, in this study, we investigated the influence of capping ligands adsorbed on gold surfaces on the formation of the gold-ligand interface. Citrate (Citr), poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), and oleylamine (Oley)-stabilized Au NPs were not activated by piperazine for the hydrogenation of alkynes, but the catalytic activity was greatly enhanced after removing the capping ligands from the gold surface by calcination at 400 °C and the subsequent adsorption of piperazine. Therefore, the capping ligand can limit the catalytic activity if not carefully removed, demonstrating the need of a cleaner surface for a ligand-metal cooperative effect in the activation of H2 for selective semihydrogenation of various alkynes under mild reaction conditions.
- Barbosa, Eduardo C. M.,Camargo, Pedro H. C.,Fiorio, Jhonatan L.,Hashmi, A. Stephen K.,Kikuchi, Danielle K.,Rossi, Liane M.,Rudolph, Matthias
-
p. 1996 - 2003
(2020/04/22)
-
- Normal Alpha Olefin Synthesis Using Dehydroformylation or Dehydroxymethylation
-
The present invention discloses processes for producing normal alpha olefins, such as 1-hexene, 1-octene, 1-decene, and 1-dodecene in a multistep synthesis scheme from another normal alpha olefin. Also disclosed are reactions for converting aldehydes, primary alcohols, and terminal vicinal diols into normal alpha olefins.
- -
-
-
- Oxidative Dehydroxymethylation of Alcohols to Produce Olefins
-
Catalyst compositions for the conversion of aldehyde compounds and primary alcohol compounds to olefins are disclosed herein. Reactions include oxidative dehydroxymethylation processes and oxidative dehydroformylation methods, which are beneficially conducted in the presence of a sacrificial acceptor of H2 gas, such as N,N-dimethylacrylamide.
- -
-
-
- An Engineered Self-Sufficient Biocatalyst Enables Scalable Production of Linear α-Olefins from Carboxylic Acids
-
Fusing the decarboxylase OleTJE and the reductase domain of P450BM3 creates a self-sufficient protein, OleT-BM3R, which is able to efficiently catalyze oxidative decarboxylation of carboxylic acids into linear α-olefins (LAOs) under mild aqueous conditions using O2 as the oxidant and NADPH as the electron donor. The compatible electron transfer system installed in the fusion protein not only eliminates the need for auxiliary redox partners, but also results in boosted decarboxylation reactivity and broad substrate scope. Coupled with the phosphite dehydrogenase-based NADPH regeneration system, this enzymatic reaction proceeds with improved product titers of up to 2.51 g L-1 and volumetric productivities of up to 209.2 mg L-1 h-1 at low catalyst loadings (~0.02 mol%). With its stability and scalability, this self-sufficient biocatalyst offers a nature-friendly approach to deliver LAOs.
- Lu, Chen,Shen, Fenglin,Wang, Shuaibo,Wang, Yuyang,Liu, Juan,Bai, Wen-Ju,Wang, Xiqing
-
p. 5794 - 5798
(2018/06/01)
-
- Chemoselective deoxygenation of ether-substituted alcohols and carbonyl compounds by B(C6F5)3-catalyzed reduction with (HMe2SiCH2)2
-
B(C6F5)3-catalyzed deoxygenation of ether-substituted alcohols and carbonyl compounds has been developed using (HMe2SiCH2)2 as the reductant. This unique reagent shows distinct superiority over traditional one silicon-centered hydrosilanes, giving the corresponding alkanes in high yields with good tolerance of ethers, aryl halides and alkenes. The control experiments suggest that (HMe2SiCH2)2 might facilitate the approach in an intramolecular Si/O activation manner.
- Yang, Wenyu,Gao, Lu,Lu, Ji,Song, Zhenlei
-
supporting information
p. 4834 - 4837
(2018/05/23)
-
- Tandem Catalysis: Transforming Alcohols to Alkenes by Oxidative Dehydroxymethylation
-
We report a Rh-catalyst for accessing olefins from primary alcohols by a C-C bond cleavage that results in dehomologation. This functional group interconversion proceeds by an oxidation-dehydroformylation enabled by N,N-dimethylacrylamide as a sacrificial acceptor of hydrogen gas. Alcohols with diverse functionality and structure undergo oxidative dehydroxymethylation to access the corresponding olefins. Our catalyst protocol enables a two-step semisynthesis of (+)-yohimbenone and dehomologation of feedstock olefins.
- Wu, Xuesong,Cruz, Faben A.,Lu, Alexander,Dong, Vy M.
-
p. 10126 - 10130
(2018/08/23)
-
- A durable nanocatalyst of potassium-doped iron-carbide/alumina for significant production of linear alpha olefins via Fischer-Tropsch synthesis
-
Improvement of activity, selectivity, and stability of the catalyst used in Fischer-Tropsch synthesis (FTS) to produce targeted hydrocarbon products has been a major challenge. In this work, the potassium-doped iron-carbide/alumina (K-Fe5C2/Al2O3), as a durable nanocatalyst containing small iron-carbide particles (~ 10 nm), was applied to high-temperature Fischer-Tropsch synthesis (HT-FTS) to optimize the production of linear alpha olefins. The catalyst, suitable under high space velocity reaction conditions (14–36 N L gcat?1 h?1) based on the well-dispersed potassium as an efficient base promoter on the active iron-carbide surface, shows very high CO conversion (up to ~90%) with extremely high activity (1.41 mmolCO gFe?1 s?1) and selectivity for C5–C13 linear alpha olefins.
- Park, Ji Chan,Jang, Sanha,Rhim, Geun Bae,Lee, Jin Hee,Choi, Hyunkyoung,Jeong, Heon-Do,Youn, Min Hye,Lee, Dong-Wook,Koo, Kee Young,Kang, Shin Wook,Yang, Jung-Il,Lee, Ho-Tae,Jung, Heon,Kim, Chul Sung,Chun, Dong Hyun
-
p. 190 - 198
(2018/08/01)
-
- Anhydride-Additive-Free Nickel-Catalyzed Deoxygenation of Carboxylic Acids to Olefins
-
A nickel-catalyzed route for direct, anhydride-additive-free deoxygenation of fatty acids to the corresponding olefins has been developed. The transformation is catalyzed by simple nickel salts of the type NiX2 (X = halide, acetate, acetylacetonate), uses PPh3 as a stoichiometric reductant, and exhibits selectivity for generation of linear α-olefin products. The reaction was rendered cocatalytic in PPh3 using 1,1,3,3-tetramethyldisiloxane (TMDS) as terminal reductant for the in situ reduction of OPPh3 and catalytic Cu(OTf)2
- John, Alex,Hillmyer, Marc A.,Tolman, William B.
-
supporting information
p. 506 - 509
(2017/04/21)
-
- Selective Decarbonylation of Fatty Acid Esters to Linear α-Olefins
-
Selective decarbonylation of p-nitrophenol esters of fatty acids to the corresponding linear α-olefins (LAOs) was achieved using palladium catalysis. After extensive ligand screening, a mixed-ligand system exploiting the trans-spanning diphosphine XantPhos and an N-heterocyclic carbene (IPr) was identified as the most effective in yielding high α-selectivity and high conversions of the ester (>98% selectivity, >90% conversion using 2.5 mol % of PdCl2 and 5 mol % of the ligands, 190 °C, 2-2.5 h). On the basis of insights from modeling at the density functional level of theory, we propose that the mixed-ligand set achieves high α-selectivity by promoting olefin dissociation from the palladium center following β-hydride elimination, which is especially facilitated both by the combined steric bias of the mixed-ligand set and by the ability of the XantPhos ligand to coordinate in both mono- and bidentate fashions.
- John, Alex,Dereli, Büsra,Ortunìo, Manuel A.,Johnson, Hillis E.,Hillmyer, Marc A.,Cramer, Christopher J.,Tolman, William B.
-
p. 2956 - 2964
(2017/08/21)
-
- Nickel-Catalyzed Cyanation of Aryl Chlorides and Triflates Using Butyronitrile: Merging Retro-hydrocyanation with Cross-Coupling
-
We describe a nickel-catalyzed cyanation reaction of aryl (pseudo)halides that employs butyronitrile as a cyanating reagent instead of highly toxic cyanide salts. A dual catalytic cycle merging retro-hydrocyanation and cross-coupling enables the conversion of a broad array of aryl chlorides and aryl/vinyl triflates into their corresponding nitriles. This new reaction provides a strategically distinct approach to the safe preparation of aryl cyanides, which are essential compounds in agrochemistry and medicinal chemistry.
- Yu, Peng,Morandi, Bill
-
supporting information
p. 15693 - 15697
(2017/12/02)
-
- CATALYTIC ESTER DECARBONYLATION
-
A process of preparing olefins of the formula (I) is described herein: with R1 being a substituted or unsubstituted (C1-C30)hydrocarbyl, and R2 being a substituted or unsubstituted (C1-C20)hydrocarbyl. The process includes reacting a compound of formula (II) wherein Ar is chosen from in the presence of a palladium-based catalyst and an organic solvent. A process of preparing olefins of the formula (III) is also described: with R3 being a substituted or unsubstituted (C1-C30)hydrocarbyl, R4 being a substituted or unsubstituted (C1-C20)hydrocarbyl, and R5 being a substituted or unsubstituted (C1-C30) hydrocarbyl. The process includes reacting a compound of formula (IV) wherein Ar is chosen from with a compound of formula (V) wherein Ar is chosen from in the presence of a palladium-based catalyst and an organic solvent.
- -
-
Paragraph 0087-0088
(2016/08/07)
-
- Synthesis of Pincer Hydrido Ruthenium Olefin Complexes for Catalytic Alkane Dehydrogenation
-
A series of new hydrido Ru(II) olefin complexes supported by isopropyl-substituted pincer ligands have been synthesized and characterized. These complexes are thermally robust and active for catalytic transfer and acceptorless alkane dehydrogenation. Notably, the alkane dehydrogenation catalysts are tolerant of a number of polar functional species.
- Zhang, Yuxuan,Fang, Huaquan,Yao, Wubing,Leng, Xuebing,Huang, Zheng
-
supporting information
p. 181 - 188
(2016/02/05)
-
- Effective deoxygenation of fatty acids over Ni(OAc)2 in the absence of H2 and solvent
-
Different metal acetate salts were systematically examined for the catalytic deoxygenation of stearic acid in the absence of H2 and solvent for the first time. Ni(OAc)2 exhibited the highest activity with 62% yield achieved at 350°C for 4.5 h with only 1 mol% (0.2 wt%) of the catalyst. Even with 0.25 mol% (0.05 wt%) catalyst, around 28% yield was achieved within 2 h at 350°C with 89% selectivity to C17 hydrocarbons. The activity based on C17 yields per Ni was 14.5 mol mol-1 h-1, considerably higher than that in previous reports. The catalytically active species were identified to be in situ generated Ni nanoparticles (8-10 nm) formed from the decomposition of the metal precursor with stearic acid as a stabilizer. A new reaction pathway of alkane formation from stearic acid via anhydride intermediate decarbonylation under an inert gas atmosphere was proposed. The excellent stability of the catalyst was demonstrated by re-adding a substrate to the system, during which the activity remained constant through four consecutive runs. The novel catalytic system was found to be applicable to a range of fatty acids and triglycerides with varying activities.
- Li, Wenjing,Gao, Yongjun,Yao, Siyu,Ma, Ding,Yan, Ning
-
p. 4198 - 4205
(2015/08/11)
-
- An alternative approach to differentially substituted 2-oxazoline chalcogen derivatives
-
In this study we present an alternative method to obtain several substituted mono or bis-2-oxazolines containing a chalcogen atom as a tether element. Alkylation of 2-tosyloximethylene-2-oxazoline with an appropriate sodium, lithium or potassium alkoxide yielded the corresponding ether. Introduction of sulfur or selenium was easily accomplished using the corresponding sodium salts. The 77Se NMR for alkyl or aryl 2-methylene-2-oxazoline selenides shows good correlation with the electronegativity pattern of substituents. Most products containing oxazolinyl-chalcogen were stable under the usual experimental conditions. However, the tellurium derivatives showed unusual sensitivity to light and oxygen, decomposing through a very complex mechanistic pathway. As a result of this oxidative process, 4,4-dimethyl-2-oxazoline-2-carbaldehyde could be isolated and fully characterized for the first time, in 17% yield.
- De Mello, Murilo B.M.,Clososki, Giuliano C.,Piovan, Leandro,De Oliveira, Alfredo R.M.
-
-
- Palladium-catalyzed decarbonylative dehydration of fatty acids for the production of linear alpha olefins
-
A highly efficient palladium-catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even-numbered natural fatty acids into valuable and expensive odd-numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent-free and relatively mild conditions.
- Liu, Yiyang,Kim, Kelly E.,Herbert, Myles B.,Fedorov, Alexey,Grubbs, Robert H.,Stoltz, Brian M.
-
supporting information
p. 130 - 136
(2014/03/21)
-
- Microbial biosynthesis of medium-chain 1-alkenes by a nonheme iron oxidase
-
Aliphatic medium-chain 1-alkenes (MCAEs, ~10 carbons) are "drop-in" compatible next-generation fuels and precursors to commodity chemicals. Mass production of MCAEs from renewable resources holds promise for mitigating dependence on fossil hydrocarbons. An MCAE, such as 1-undecene, is naturally produced by Pseudomonas as a semivolatile metabolite through an unknown biosynthetic pathway. We describe here the discovery of a single gene conserved in Pseudomonas responsible for 1-undecene biosynthesis. The encoded enzyme is able to convert medium-chain fatty acids (C10-C14) into their corresponding terminal olefins using an oxygen-activating, nonheme iron-dependent mechanism. Both biochemical and X-ray crystal structural analyses suggest an unusual mechanism of β-hydrogen abstraction during fatty acid substrate activation. Our discovery unveils previously unidentified chemistry in the nonheme Fe(II) enzyme family, provides an opportunity to explore the biology of 1-undecene in Pseudomonas, and paves the way for tailored bioconversion of renewable raw materials to MCAE-based biofuels and chemical commodities.
- Rui, Zhe,Li, Xin,Zhu, Xuejun,Liu, Joyce,Domigan, Bonnie,Barr, Ian,Cate, Jamie H. D.,Zhang, Wenjun
-
p. 18237 - 18242
(2015/02/19)
-
- Regioselective allene hydroarylation via one-pot allene hydrosilylation/Pd-catalyzed cross-coupling
-
Advances in hydroarylation have been achieved by the development of a one-pot regioselective allene hydrosilylation/Pd(0)-catalyzed cross-coupling protocol. The regioselectivity is primarily governed by N-heterocyclic carbene (NHC) ligand identity in the hydrosilylation step and is preserved in the subsequent cross-coupling reaction. This methodology affords streamlined access to functionalized 1,1-disubstituted alkenes with excellent regiocontrol. (Chemical Equation Presented).
- Miller, Zachary D.,Montgomery, John
-
supporting information
p. 5486 - 5489
(2015/01/09)
-
- Tandem isomerization-decarboxylation for converting alkenoic fatty acids into alkenes
-
We report a facile Ru-catalyzed route to alkenes from unsaturated fatty acids (alkenoic fatty acids) via readily accessible catalyst precursors, [Ru(CO)2RCO2]n and Ru3(CO)12. The catalyst apparently functions in a tandem mode by dynamically isomerizing the positions of double bonds in an aliphatic chain and, subsequently, decarboxylating specific isomers with lower activation barriers. Substrates capable of tandem isomerization-decarboxylation processes (oleic acid, undecylenic acid) are readily converted to mixtures of alkenes. A catalytic cycle is proposed that relies on isomerization positioning double bonds proximate to the acid function to enable facile decarboxylation. To elucidate the proposed mechanistic pathway, substrates that do not undergo decarboxylation under these catalytic conditions (methyl oleate) are compared with those that cannot isomerize the position of unsaturation (cinnamic acid). Both were shown to be operational under these catalytic reaction conditions. Another illustrative comparison shows that the saturated octadecanoic acid is 28 times less reactive than the unsaturated counterpart when reacted using this precatalyst.
- Murray, Rex E.,Walter, Erin L.,Doll, Kenneth M.
-
p. 3517 - 3520
(2015/02/19)
-
- PALLADIUM-CATALYZED DECARBONYLATION OF FATTY ACID ANHYDRIDES FOR THE PRODUCTION OF LINEAR ALPHA OLEFINS
-
The present invention is directed to methods of forming olefins, especially linear alpha olefins from fatty acids or anhydrides, each method comprising: contacting an amount of precursor carboxylic acid anhydride with a palladium catalyst comprising a bidentate bis-phosphine ligand in a reaction mixture so as to form an olefin in a product with the concomittant formation and removal of CO and water from the reaction mixture, either directly or indirectly, wherein the reaction mixture is maintained with a sub-stoichiometric excess of a sacrificial carboxylic acid anhydride, an organic acid, or both, said sub-stoichiometric excess being relative to the amount of the precursor carboxylic acid anhydride. The precursor carboxylic acid anhydride may be added to the reaction mixture directly or formed in situ by the reaction between at least one precursor carboxylic acid with a stoichiometric amount of the sacrificial acid anhydride.
- -
-
Page/Page column
(2014/06/23)
-
- Copper-catalyzed trifluoromethylthiolation of primary and secondary alkylboronic acids
-
A Cu-catalyzed trifluoromethylthiolation of primary and secondary alkylboronic acids with an electrophilic trifluoromethylthiolating reagent is described. Tolerance for a variety of functional groups was observed.
- Shao, Xinxin,Liu, Tianfei,Lu, Long,Shen, Qilong
-
supporting information
p. 4738 - 4741
(2015/04/27)
-
- Copper-catalyzed alkyl-alkyl cross-coupling reactions using hydrocarbon additives: Efficiency of catalyst and roles of additives
-
Cross-coupling of alkyl halides with alkyl Grignard reagents proceeds with extremely high TONs of up to 1230000 using a Cu/unsaturated hydrocarbon catalytic system. Alkyl fluorides, chlorides, bromides, and tosylates are all suitable electrophiles, and a TOF as high as 31200 h-1 was attained using an alkyl iodide. Side reactions of this catalytic system, i.e., reduction, dehydrohalogenation (elimination), and the homocoupling of alkyl halides, occur in the absence of additives. It appears that the reaction involves the β-hydrogen elimination of alkylcopper intermediates, giving rise to olefins and Cu-H species, and that this process triggers both side reactions and the degradation of the Cu catalyst. The formed Cu-H promotes the reduction of alkyl halides to give alkanes and Cu-X or the generation of Cu(0), probably by disproportionation, which can oxidatively add to alkyl halides to yield olefins and, in some cases, homocoupling products. Unsaturated hydrocarbon additives such as 1,3-butadiene and phenylpropyne play important roles in achieving highly efficient cross-coupling by suppressing β-hydrogen elimination, which inhibits both the degradation of the Cu catalyst and undesirable side reactions.
- Iwasaki, Takanori,Imanishi, Reiko,Shimizu, Ryohei,Kuniyasu, Hitoshi,Terao, Jun,Kambe, Nobuaki
-
p. 8522 - 8532
(2015/01/08)
-
- Gold nanocluster-catalyzed semihydrogenation: A unique activation pathway for terminal alkynes
-
We report high catalytic activity of ultrasmall spherical Au 25(SC2H4Ph)18 and rod-shaped Au 25(PPh3)10(C≡CPh)5X 2 (X = Br, Cl) nanoclusters supported on oxides for the semihydrogenation of terminal alkynes into alkenes with >99% conversion of alkynes and ~100% selectivity for alkenes. In contrast, internal alkynes cannot be catalyzed by such "ligand-on" Au25 catalysts; however, with "ligand-off" Au25 catalysts the internal alkynes can undergo semihydrogenation to yield Z-alkenes, similar to conventional gold nanoparticle catalysts. On the basis of the results, a unique activation pathway of terminal alkynes by "ligand-on" gold nanoclusters is identified, which should follow a deprotonation activation pathway via a R′-C≡C-[AunLm] (where L represents the protecting ligands on the cluster), in contrast with the activation mechanism on conventional gold nanocatalysts. This new activation mode is supported by observing the incorporation of deprotonated -C≡CPh as ligands on rod-shaped Au25(PPh3)10(C≡ CPh)5X2 nanoclusters under conditions similar to the catalytic reaction and by detecting the R′-C≡C-[Au n(SC2H4Ph)m] via FT-IR spectroscopy.
- Li, Gao,Jin, Rongchao
-
p. 11347 - 11354
(2014/11/08)
-
- Investigation of hydrocarbon generation mechanism by polarizing the carboxy-group of fatty acid salt with microwave radiation
-
Triglycerides can be converted to renewable hydrocarbons fuel which can be used as engine fuels by alkali pyrolysis decarboxylation and cracking processes. The purpose of present study was to explore decarboxylation mechanism of fatty acid salt with microwave radiation. Sodium stearate, potassium stearate, sodium oleate and sodium laurate was chosen as a model compound. The carboxy-terminal of this dipolar molecule was further polarized with microwave radiation. The Lorentz force of ions of dipolar molecules were moved in accordance with the way of electromagnetic waves, contribute to the formation of carbanion, which effectively promote the decarboxylation reaction. Moreover, the polarity of carboxy-terminal was stronger, more easily decarboxylation. The surface of glycerol formed a High-Temperature Locus in microwave radiation reaction system, facilitate the decarboxylation processe, in adition to played a role as the hydrogen donor for this high dielectric value compound. C8-C20 n-alkanes and n-alk-1-enes were arranged regular in liquid products. It proved the feasibility to derive renewable hydrocarbon fuel from sodium salt of fatty acids by microwave pyrolysis.
- Wang,Liu,Ruan,Wen,Wan,Zhang
-
p. 369 - 375
(2014/06/09)
-
- A practical procedure for iron-catalyzed cross-coupling reactions of sterically hindered aryl-grignard reagents with primary alkyl halides
-
Although iron-catalyzed cross-coupling reactions of arylmagnesium halides with alkyl halides are well established and proceed effectively under a variety of experimental conditions, they often find limitations when working with sterically hindered aryl-Grignard reagents. Outlined in this paper is a practical solution that allows this gap in coverage to be filled. Specifically, it is shown that bis(diethylphosphino)ethane (depe) crafts an effective coordination environment about Fe(+2). This commercially available ligand is slim enough not to interfere with the loading of the iron center even by ortho,ortho-disubstituted arylmagnesium halides, yet capable of preventing premature reductive coupling of the resulting organoiron species, which seem to be hardly basic either. The reaction is compatible with various polar functional groups as well as with substrates containing β-heteroatom substituents. Moreover, the procedure even allows encumbered neopentylic electrophiles to be arylated with donors as bulky as mesitylmagnesium bromide, whereas secondary alkyl halides tend to eliminate.
- Sun, Chang-Liang,Krause, Helga,Fuerstner, Alois
-
p. 1281 - 1291
(2014/05/06)
-
- Synthesis of (2-alkylthiothiazolin-5-yl)methyl dodecanoates via tandem radical reaction
-
A series of (2-alkylthiothiazolin-5-yl)methyl dodecanoates was synthesized from various alkyl N-allylcarbamodithioates and dilauroyl peroxide via a tandem radical hydrogen-abstraction-cyclization-substitution/combination reaction with a 5-exo-trig radical cyclization as a key step. The current route is the first, convenient, and efficient synthesis of (2-alkylthiothiazolin-5-yl)methanol derivatives. The Royal Society of Chemistry.
- Kakaei, Saeed,Xu, Jiaxi
-
p. 5481 - 5490
(2013/08/28)
-
- Dual role of allylsamarium bromide as a Grignard reagent and a single electron transfer reagent in the one-pot synthesis of terminal olefins
-
The utility of allylsamarium bromide, both as a nucleophilic reagent and a single-electron transfer reagent, in the reaction of carbonyl compounds with allylsamarium bromide in the presence of diethyl phosphate is reported in this communication. From a synthetic point of view, a simple one-pot method for the preparation of terminal olefins is developed.
- Li, Ying,Hu, Yuan-Yuan,Zhang, Song-Lin
-
supporting information
p. 10635 - 10637
(2013/11/06)
-
- Total synthesis and antifungal activity of (2S,3R)-2-aminododecan-3-ol
-
We report the total synthesis of (2S,3R)-2-aminododecan-3-ol has been achieved starting from commercially available 10-undecenoic acid. The key steps involved are Sharpless asymmetric epoxidation, Miyashita's boron-directed C-2 regioselective azidolysis, generated the asymmetric centers and in situ detosylation and reduction of azido tosylate. The antifungal activity of the synthesized (2S,3R)-2-aminododecan-3-ol was evaluated on several Candida strains and was comparable to miconazole, a standard drug.
- Vijai Kumar Reddy,Prabhavathi Devi,Prasad,Poornima,Ganesh Kumar
-
p. 4678 - 4680
(2012/08/07)
-
- Ligandless iron-catalyzed desulfinylative C-C allylation reactions using Grignard reagents and alk-2-enesulfonyl chlorides
-
Alk-2-enesulfonyl chlorides 1-4 were synthesized by the BCl3-promoted ene reaction of alkenes with SO2. These sulfonyl chlorides were then used as electrophilic partners in iron-catalyzed desulfinylative cross-coupling reactions with different Grignard reagents (aromatic, aliphatic, and heteroaromatic). The reaction can be catalyzed with even 2 mol-% of the simple iron salt Fe(acac)3. The regioselectivity of these allylations was studied by using sulfonyl chlorides 3 and 4 with aryl Grignard reagents. The scope of these allylations was further extended by the coupling of ester-substituted alk-2-enesulfonyl chloride 10 with aromatic Grignard reagents. Symmetrical products were synthesized by double C-C allylation with the use of 2-methylidenepropane-1,3-disulfonyl chloride (12). Wiley-VCH Verlag GmbH & Co. KGaA.
- Volla, Chandra M. R.,Markovic, Dean,Dubbaka, Srinivas Reddy,Vogel, Pierre
-
experimental part
p. 6281 - 6288
(2011/02/28)
-
- Palladium-catalyzed desulfinylative C-C allylation of Grignard reagents and enolates using allylsulfonyl chlorides and esters
-
2-Methylprop-2-ene-, prop-2-ene-, 1-methylprop-2-ene-, and (E)-but-2-enesulfonyl chlorides have been used as electrophilic partners in desulfinylative palladium-catalyzed C-C coupling with Grignard reagents and sodium salts of dimethyl malonate and methyl
- Rao Volla, Chandra M.,Dubbaka, Srinivas Reddy,Vogel, Pierre
-
experimental part
p. 504 - 511
(2009/04/07)
-
- Hydroindation of allenes and its application to radical cyclization
-
Hydroindation of allenes and radical cyclization of 1,2,7-trienes (allenenes) were accomplished by HInCl2 with high regioselectivity to afford a variety of cyclic compounds. The resulting vinylic indiums could be used for successive coupling reactions in a one-pot procedure. The use of HInCl2 generated slowly in situ is extremely effective for the radical cyclization. The Royal Society of Chemistry.
- Hayashi, Naoki,Hirokawa, Yusuke,Shibata, Ikuya,Yasuda, Makoto,Baba, Akio
-
supporting information; experimental part
p. 1949 - 1954
(2009/01/31)
-
- Polycyclic aromatic compounds-mediated electrochemical reduction of alkyl mesylates
-
Electrochemical reduction of alkyl mesylates was successfully carried out by using an undivided cell equipped with a Pt cathode and an Mg anode in the presence of biphenyl and t-BuOH. The reaction could proceed efficiently under mild conditions to give the corresponding alkanes in moderate to good yields. This procedure could also be applicable to chemoselective reduction of mesylates having functional groups such as epoxide, olefin, acetal, hydroxy, or cyano groups. Copyright
- Senboku, Hisanori,Takahashi, Megumi,Fukuhara, Tsuyoshi,Hara, Shoji
-
p. 228 - 229
(2008/02/04)
-
- Method of increasing the carbon chain length of olefinic compounds
-
According to the present invention there is provided a process of increasing the carbon chain length of an olefinic compound comprising the steps of providing a starting olefinic compound and subjecting it to hydroformylation to produce an aldehyde and/or alcohol with an increased carbon chain length compared to the starting olefinic compound. Optionally, the aldehyde that may form during the hydroformylation reaction is hydrogenated to convert it to an alcohol which has an increased carbon chain length compared to the starting olefinic compound. The alcohol with the increased carbon chain length is subjected to dehydration to produce an olefinic compound with an increased carbon chain length compared to the starting olefinic compound. The invention also relates to olefinic compounds produced by the process.
- -
-
Page/Page column 3
(2008/06/13)
-
- A mild and efficient protocol for the conversion of carboxylic acids to olefins by a catalytic decarbonylative elimination reaction
-
A new method for the conversion of aliphatic carboxylic acids to olefins under unprecedented mild conditions is disclosed, wherein the carboxylic acids are converted in situ with pivalic anhydride to the mixed anhydrides, which regioselectively add to a PdCl2-DPE-Phos catalyst. At a temperature of only 110°C, smooth decarbonylation and β-hydride elimination occur, and the corresponding olefins along with CO, CO2 and pivalic acid are liberated.
- Goossen, Lukas J.,Rodriguez, Nuria
-
p. 724 - 725
(2007/10/03)
-
- Semivolatile and volatile compounds in combustion of polyethylene
-
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
-
p. 615 - 627
(2007/10/03)
-
- Novel nickel-catalyzed coupling reaction of allyl ethers with chlorosilanes, alkyl tosylates, or alkyl halides promoted by vinyl-Grignard reagent leading to allylsilanes or alkenes
-
A new method for a carbon-silicon or carbon-carbon bond forming reaction between allyl ethers and chlorosilanes, alkyl tosylates, or alkyl halides giving rise to allylsilanes or alkenes has been developed. This reaction proceeds efficiently at ambient temperature by the combined use of nickel catalysts and a vinyl-Grignard reagent. A possible reaction pathway involving the formation of allyl-Grignard reagents via transmetallation of π-allylnickel complexes with the vinyl-Grignard reagent and subsequent trapping of the thus formed allyl-Grignard reagents with electrophiles is proposed.
- Terao, Jun,Watabe, Hiroyasu,Watanabe, Hiroyuki,Kambe, Nobuaki
-
p. 1674 - 1678
(2007/10/03)
-
- Synthesis and transformations of metallacycles 28. Reactions of allenes with EtAlCl2 and Et2AlCl catalyzed by Ti and Zr complexes
-
Catalytic cycloalumination of allenes with EtAlCl2 in the presence of Ti or Zr complexes afforded methylidene- and alkyl(benzyl)idenealuminacyclopropanes and the corresponding aluminacyclopentanes, which were identified by analyzing the hydroly
- Ibragimov,Khafizova,Gil'fanova,Dzhemilev
-
p. 2255 - 2260
(2007/10/03)
-
- An efficient method for conversion of 1-alken-3-yl carbonates to 1- alkenes and 3-chloro-1-alkenes via allyltitaniums
-
Hydrolysis and halogenolysis of the allyltitaniums derived from allylic carbonates and a Ti(O-i-Pr)4/2 i-PrMgCl reagent proceed with high regio- and stereoselectivity, thus providing an efficient method for converting 1- alken-3-yl carbonates to 1-alkenes or 3-chloro-1-alkenes.
- Matsuda, Shin-Ichiro,An, Duk Keun,Okamoto, Sentaro,Sato, Fumie
-
p. 7513 - 7516
(2007/10/03)
-
- Generation of allylic manganates from trimethylmanganate and allylic stannanes and their reactions with epoxides
-
A new method for forming allyldimethylmanganate has been developed. The preparation eliminated the need for prior generation of an allylmetal species such as allyllithium or allylmagnesium compounds. The reagents reacted with epoxides to give allylated products exclusively in good yields.
- Tang, Jun,Yorimitsu, Hideki,Kakiya, Hirotada,Inoue, Rie,Shinokubo, Hiroshi,Oshima, Koichiro
-
p. 9019 - 9022
(2007/10/03)
-
- Radical Nature of Pathways to Alkene and Ester from Thermal Decomposition of Primary Alkyl Diacyl Peroxide
-
Thermal decomposition of a primary alkyl diacyl peroxide 2 is investigated.Dependence of product yields on temperature, viscosity, and solvent polarity is examined in a variety of media.The excess of the alkene disproportionation product 4 and the presence of ester 3 and acid 5 is argued to demonstrate the existence of a discrete acyloxy-alkyl geminate radical pair.Stereoselective deuterium labeling of 2 and subsequent 1H-NMR analysis of the resulting isotopomers of 4 confirm the radical nature of detected decomposition products.
- Ryzhkov, Lev R.
-
p. 2801 - 2808
(2007/10/03)
-
- Alkylidenation of Ketones by gem-Dibromoalkane, SmI2, and Sm in the Presence of Catalytic Amount of CrCl3
-
Alkylidenation of ketones can be performed by the reaction with geminal dibromoalkane-SmI2-Sm in the presence of catalytic amount of CrCl3 at room temperature yielding the alkylidenated products in good to excellent yields.
- Matsubara, Seijiro,Horiuchi, Miyuki,Takai, Kazuhiko,Utimoto, Kiitiro
-
p. 259 - 260
(2007/10/02)
-
- Pyrolysis of Alkyl Acetates. A Radical Pathway for the Formation of Minor Products
-
Decyl acetate and decene pyrolysis under the same reaction conditions show that the formation of the minor products during the pyrolysis of esters occurs by a parallel, and not a secondary, reaction.The radioactivity observed in the CO2 and CO produced during the pyrolysis of 1-hexyl acetate-1-14C and the radioactivity in the methane from the pyrolysis of 1-hexyl acetate-2-14C strongly suggested a radical reaction pathway for the formation of the minor products.Considering the above results together with the radioactivity data of gas samples from the pyrolysis of 1-decyl-1-14C acetate, 1-hexyl-1-14C acetate, and 1-heptadecyl-1-14C acetate leads to the conclusion that the mechanism of pyrolysis of esters may be viewed as a cyclo-DEDNAN mechanism for the formation of the major alkene product and a radical mechanism for the formation of minor products.A useful synthetic procedure for the preparation of high carbon number alkenes (>10) also results from this study.
- Shi, Buchang,Ji, Ying,Dabbagh, Hossein A.,Davis, Burtron H.
-
p. 845 - 849
(2007/10/02)
-
- A Highly Catalytic and Selective Conversion of Carboxylic Acids to 1-Alkenes of One Less Carbon Atom
-
An equimolar mixture of a carboxylic acid and acetic anhydride produces a reagent combination that undergoes a highly efficient decarbonylation/dehydration at 250 deg C using either Pd- or Rh-based catalyst systems, affording excellent yields of the corresponding 1-alkenes of one less carbon atom.
- Miller, Joseph A.,Nelson, Jeffrey A.,Byrne, Michael P.
-
-
- Stereochemistry of direct olefin formation from carbonyl compounds and lithiated heterocyclic sulfones
-
The conditions for the title reaction were studied for the 2-benzothiazole and 2-pyridine series and for some examples in the 2-pyrimidine series.The olefin preparations were generally observed to be more efficient for 2-BT-sulfone systems.From the data of the hundred cases studied, it can be concluded that (E)-olefins are obtained: (i) from saturated BT-sulfones and aromatic aldehydes; and (ii) from benzylic BT-sulfones and branched saturated aldehydes (isobutyraldehyde, pivalaldehyde) or α,β-ethylenic or aromatic aldehydes. (Z)-olefins arise: (i) fom propargylic BT-sulfones and saturated or aromatic aldehydes; and (ii) from allylic or benzylic Pyr-sulfones and saturated aldehydes.Possible mechanisms for this new olefination procedure were examined. - heteroaromatic sulfones, organolithium derivatives, intramolecular ipso reactions, stereochemistry, elimination, olefination.
- Baudin, J. B.,Hareau, G.,Julia, S. A.,Lorne, R.,Ruel, O.
-
p. 856 - 878
(2007/10/02)
-
- Hindered organoboron groups in organic chemistry. 24. The condensation of aliphatic aldehydes with dimesitylboron stabilised carbanions to give ketones
-
The condensation of boron stabilised carbanions, MeS2BCHLiR1, (R1≠H) with aliphatic aldehydes, R2CHO, followed by treatment with trifluoroacetic anhydride (TFAA) or N-chlorosuccinimide (NCS) is an unique, broadly applicable redox process that yields ketones, R1CH2COR2, directly and in high yields. The anion MeS2BCH2Li (MeS2BCHLiR1, R1=H) gives high yields of alkenes, R2CH=CH2 in the same conditions.
- Pelter, Andrew,Smith, Keith,Elgendy, Said M. A.,Rowlands, Martin
-
p. 7104 - 7118
(2007/10/02)
-
- Desulfurization with Nickel and Cobalt Boride: Scope, Selectivity, Stereochemistry, and Deuterium-Labeling Studies
-
A variety of organosulfur compounds containing alkylthio and arylthio groups underwent reductive desulfurization under notably mild conditions when treated with nickel boride, generated in situ from nickel chloride hexahydrate and sodium borohydride in methanol-THF (3:1).Phenyl, chloro, and ester groups are not reduced under these conditions, while iodo, bromo, nitrile, aldehyde, ketone, cyclopropane, and olefinic functions are reduced either completely or partially.Deuterium-labeling studies indicate that the hydrogen that is incorporated into the product originates from both the sodium borohydride and the protic solvent, suggesting the intermediacy of dihydrogen.The epimers 3α- and 3β-(phenylthio)cholestane afforded 3α- and 3β-deuteriocholestane, respectively, demonstrating that the reaction proceeds with retention of configuration.The method may thus be employed for the stereospecific preparation of deuterated products from organosulfur compounds.Arguments are presented in support of a tentative mechanism involving an oxidative addition-reductive elimination sequence via a nickel hydride intermediate.
- Back, Thomas G.,Baron, Denise L.,Yang, Kexin
-
p. 2407 - 2413
(2007/10/02)
-
- Radical addition of 2,2,2-trifluoroethyl iodide to terminal alkenes
-
2,2,2-Trifluoroethyl iodide adds to terminal alkenes under free radical conditions in good yields if the radical initiator is added in successive portions to the reaction mixture. Reduction of the resulting secondary iodides with sodium borohydride gives the corresponding trifluoroethyl-substituted products in overall yields of 40-60%. The reaction seems to be restricted to vinyl double bonds.
- Cloux,Kovats
-
p. 409 - 412
(2007/10/02)
-