- Method for synthesizing 1, 2-disubstituted olefin through reaction of terminal group olefin and sulfoxide
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The invention discloses a method for synthesizing 1, 2-disubstituted olefin by reaction of terminal olefin and sulfoxide. According to the method, terminal olefin with sulfoxide make reaction in one pot in the presence of ferric salt and hydrogen peroxide to generate the 1, 2-disubstituted olefin. sulfoxide is simultaneously used as a hydrocarbylation reagent and a solvent of olefin, and a reaction product is 1, 2-disubstituted olefin of which a terminal carbon atom in terminal olefin is coupled with a sulfoxide alkyl group, so that an olefin carbon chain is increased; the reaction conditionsare mild, the selectivity is high, the yield is high, and industrial production is facilitated.
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Paragraph 0053-0054; 0057-0062; 0082
(2021/02/10)
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- Method for synthesizing alkyl olefin through coupling of double-bond carbon-hydrogen bond and saturated carbon-hydrogen bond
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The invention discloses a method for synthesizing alkyl olefin through coupling of a double-bond carbon-hydrogen bond and a saturated carbon-hydrogen bond. According to to the method, one-pot reactionis implemented on olefin and sulfoxide in the presence of ferric salt and hydrogen peroxide to generate alkyl olefin; in the method, sulfoxide is simultaneously used as a hydrocarbylation reagent anda solvent of olefin, and a reaction product is alkyl olefin from sulfoxide alkyl coupled with olefin carbon atoms, so that an olefin carbon chain is increased; the reaction conditions are mild, the selectivity is good, the yield is high, and industrial production is facilitated.
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Paragraph 0074-0077; 0107
(2021/02/10)
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- METHODS OF BORYLATION AND USES THEREOF
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The present invention relates, in general terms, to methods of borylation and uses thereof. In particular, the present invention provides a method of borylating an alkene compound by contacting the compound with a boron compound, a Fe pre-catalyst and a protic additive. The borylation occurs at a vicinal (β) position to an electron donating or electron withdrawing moiety of the compound.
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Page/Page column 58
(2021/04/30)
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- Base-Mediated Site-Selective Hydroamination of Alkenes
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We present a base-mediated hydroamination protocol, using substoichiometric amounts of a hydrosilane and potassium tertbutoxide, that operates under mild conditions at 30 °C. Many aryl- and heteroatom-substituted olefins as well as arylamines are tolerated, affording the desired products with complete regioselectivity. Preliminary mechanistic investigations reveal a non-radical pathway for hydroamination. A sequential remote hydroamination strategy involving an initial Fe-catalysed olefin isomerisation followed by our base-mediated hydroamination was also developed to directly access-arylamines from terminal aliphatic alkenes.
- Koh, Ming Joo,Lee, Boon Chong,Li, Ping,Zhang, Xiaoxiang
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supporting information
(2021/12/29)
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- Iron-Catalyzed Tunable and Site-Selective Olefin Transposition
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The catalytic isomerization of C-C double bonds is an indispensable chemical transformation used to deliver higher-value analogues and has important utility in the chemical industry. Notwithstanding the advances reported in this field, there is compelling demand for a general catalytic solution that enables precise control of the C═C bond migration position, in both cyclic and acyclic systems, to furnish disubstituted and trisubstituted alkenes. Here, we show that catalytic amounts of an appropriate earth-abundant iron-based complex, a base and a boryl compound, promote efficient and controllable alkene transposition. Mechanistic investigations reveal that these processes likely involve in situ formation of an iron-hydride species which promotes olefin isomerization through sequential olefin insertion/β-hydride elimination. Through this strategy, regiodivergent access to different products from one substrate can be facilitated, isomeric olefin mixtures commonly found in petroleum-derived feedstock can be transformed to a single alkene product, and unsaturated moieties embedded within linear and heterocyclic biologically active entities can be obtained.
- Yu, Xiaolong,Zhao, Haonan,Li, Ping,Koh, Ming Joo
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supporting information
p. 18223 - 18230
(2020/12/04)
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- Dealkenylative Alkenylation: Formal σ-Bond Metathesis of Olefins
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The dealkenylative alkenylation of alkene C(sp3)?C(sp2) bonds has been an unexplored area for C?C bond formation. Herein 64 examples of β-alkylated styrene derivatives, synthesized through the reactions of readily accessible feedstock olefins with β-nitrostyrenes by ozone/FeII-mediated radical substitutions, are reported. These reactions proceed with good efficiencies and high stereoselectivities under mild reaction conditions and tolerate an array of functional groups. Also demonstrated is the applicability of the strategy through several synthetic transformations of the products, as well as the syntheses of the natural product iso-moracin and the drug (E)-metanicotine.
- Kwon, Ohyun,Sadykhov, Gusein,Swain, Manisha,Wang, Ruoxi
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supporting information
p. 17565 - 17571
(2020/09/01)
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- Enzymatic Primary Amination of Benzylic and Allylic C(sp3)-H Bonds
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Aliphatic primary amines are prevalent in natural products, pharmaceuticals, and functional materials. While a plethora of processes are reported for their synthesis, methods that directly install a free amine group into C(sp3)-H bonds remain unprecedented. Here, we report a set of new-to-nature enzymes that catalyze the direct primary amination of C(sp3)-H bonds with excellent chemo-, regio-, and enantioselectivity, using a readily available hydroxylamine derivative as the nitrogen source. Directed evolution of genetically encoded cytochrome P411 enzymes (P450s whose Cys axial ligand to the heme iron has been replaced with Ser) generated variants that selectively functionalize benzylic and allylic C-H bonds, affording a broad scope of enantioenriched primary amines. This biocatalytic process is efficient and selective (up to 3930 TTN and 96percent ee), and can be performed on preparative scale.
- Jia, Zhi-Jun,Gao, Shilong,Arnold, Frances H.
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supporting information
p. 10279 - 10283
(2020/07/27)
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- Controllable Isomerization of Alkenes by Dual Visible-Light-Cobalt Catalysis
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We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor–acceptor dye 4CzIPN accelerates the reaction further. Transformation of exocyclic alkenes into the corresponding endocyclic products could be efficiently realized by using 4CzIPN and Co(acac)2 in the absence of any additional ligands. Spectroscopic and spectroelectrochemical investigations indicate CoI being involved in the generation of a Co hydride, which subsequently adds to alkenes initiating the isomerization.
- Meng, Qing-Yuan,Schirmer, Tobias E.,Katou, Kousuke,K?nig, Burkhard
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p. 5723 - 5728
(2019/04/03)
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- Iron catalyzed methylation and ethylation of vinyl arenes
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Short alkyl chain Heck (type) reactions, especially methyl Heck reactions, are a difficult aspect of the alkyl Heck reaction. To provide a solution to this problem, iron-catalyzed methyl, ethyl and propyl Heck reactions were developed using readily available alkyl peroxides as alkyl sources. The reaction conditions were mild, clean, and easy to handle. No additive was needed, and no hazardous waste was generated. The products were obtained in up to 99% yield of one isomer for most situations. This reaction works for many types of olefin and tolerates a variety of functional groups. Several late-stage functionalizations of natural products and drug molecules were conducted to demonstrate the synthetic applications of this reaction.
- Zhu, Nengbo,Zhao, Jianguo,Bao, Hongli
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p. 2081 - 2085
(2017/03/09)
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- Improvements and Applications of the Transition Metal-Free Asymmetric Allylic Alkylation using Grignard Reagents and Magnesium Alanates
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Two new N-heterocyclic carbene (NHC) ligands have been synthesized and employed in the transition metal-free asymmetric allylic alkylation (AAA) mediated by Grignard reagents and magnesium alanates. The employment of these ligands showed high yields and improved regio- and enantioselectivity in the formation of tertiary and quaternary stereocenters. Moreover, the low catalyst loading (up to 0.3 mol%) and high scalability (up to 10 mmol) of this improved methodology provide a convenient access to biologically active compounds and synthetically valuable intermediates.
- Grassi, David,Alexakis, Alexandre
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supporting information
p. 3171 - 3186
(2015/11/03)
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- Role of sterically demanding chiral dirhodium catalysts in site-selective C-H functionalization of activated primary C-H bonds
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The influence of sterically demanding dirhodium tetracarboxylate catalysts on the site selectivity of C-H functionalization by means of rhodium carbene-induced C-H insertion is described. The established dirhodium tetraprolinate-catalyzed reactions of aryldiazoacetates cause preferential C-H functionalization of secondary C-H bonds as a result of competing steric and electronic effects. The sterically more demanding dirhodium tetrakis(triarylcyclopropanecarboxylate) catalysts, exemplified by dirhodium tetrakis[(R)-(1-(biphenyl)-2,2-diphenylcyclopropanecarboxylate)] [Rh 2(R-BPCP)4], favor C-H functionalization of activated primary C-H bonds. Highly site-selective and enantioselective C-H functionalization of a variety of simple substrates containing primary benzylic, allylic, and methoxy C-H bonds was achieved with this catalyst. The utility of this approach has been demonstrated by the late-stage primary C-H functionalization of (-)-∝-cedrene and a steroid.
- Qin, Changming,Davies, Huw M. L.
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supporting information
p. 9792 - 9796
(2014/07/22)
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- Iron-catalysed, hydride-mediated reductive cross-coupling of vinyl halides and Grignard reagents
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An iron-catalysed, hydride-mediated reductive cross-coupling reaction has been developed for the preparation of alkanes. Using a bench-stable iron(ii) pre-catalyst, reductive cross-coupling of vinyl iodides, bromides and chlorides with aryl- and alkyl Grignard reagents successfully gave the products of formal sp3-sp3 cross-coupling reactions.
- Le Bailly, Bryden A. F.,Greenhalgh, Mark D.,Thomas, Stephen P.
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supporting information; experimental part
p. 1580 - 1582
(2012/03/26)
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- A mild method for indium(III)-catalyzed 1,4-hydrosilylation of α,β-enone esters with triethylsilane and trifluoroacetic acid
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A chemo- and stereoselective 1,4-hydrosilylation of α,β-enone esters was developed using triethylsilane and trifluoroacetic acid under indium chloride catalysis. Georg Thieme Verlag Stuttgart ? New York.
- Xing, Ping,Zang, Wei,Huang, Zuo-Gang,Zhan, Yue-Xiong,Zhu, Chuan-Jun,Jiang, Biao
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p. 2269 - 2273
(2012/10/30)
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- Highly selective dimerization of styrenes and linear co-dimerization of styrenes with ethylene catalyzed by a ruthenium complex
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(Chemical Equation Presented) Heads you win: An unusual head-to-head dimerization of styrenes has been developed using the zero-valent ruthenium catalyst [Ru(η6-cot)(η2-dmfm)2] (cot = 1,3,5-cyclooctatriene, dmfm = dimethyl fumarate) in the presence of primary alcohols to give the homo-dimer in high regio- and stereoselectivity. The catalyst system is also effective for the selective co-dimerization of styrenes with ethylene to give the co-dimer in high yield.
- Kondo, Teruyuki,Takagi, Daisuke,Tsujita, Hiroshi,Ura, Yasuyuki,Wada, Kenji,Mitsudo, Take-Aki
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p. 5958 - 5961
(2008/09/18)
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- Copper catalyzed enantioselective allylic substitution by MeMgX
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Methyl Grignard undergoes highly regio (>90/10) and enantioselective (ee 91-96%) copper catalyzed allylic substitution on cinnamyl-type chlorides. CuBr (3%) and 3.3% of a chiral phosphoramidite ligand are sufficient for a complete reaction. The synthesis of a precursor of (+)-Naproxen is described. The reaction can be extended to alkyl substituted allylic chlorides (ee 72%).
- Tissot-Croset, Karine,Alexakis, Alexandre
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p. 7375 - 7378
(2007/10/03)
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- Free radical reactions to generate alkenes and/or ionic reactions to generate hydroximoyl chlorides when β-nitrostyrenes react with triethylaluminium or diethylaluminium chloride
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β-Nitrostyrenes 1 react with triethylaluminium or diethylaluminium chloride in diethyl ether solution and under nitrogen or argon to generate the alkenes 2 and the hydroximoyl chlorides 3 after work-up with ice-cold, cone, hydrochloric acid. The formation of the alkenes 2 is proposed to be a free-radical reaction via NO2/alkyl substitution since the yields of the alkenes 2 are increased in the presence of benzoyl peroxide (Bz2O2) and decreased in the presence of galvinoxyl. Only the alkenes 2 are produced with a high stereoselectivity for the E isomers when β-nitrostyrenes react with triethylaluminium in the presence of one to two equivalents of Bz2O2 as free-radical initiator. The mechanism of the generation of the hydroximoyl chlorides 3 is proposed to proceed through a 1,4-addition pathway to produce nitronates A, then the protonated nitronates B or the nitroso cations C are trapped by chloride ion to form the final products. The yields of compounds 3 are also improved by the presence of Lewis acids such as MgCl2. Medium to high yields of the hydroximoyl chlorides 3 and traces or low yields of the alkenes 2 are generated when triethylaluminium or diethylaluminium chloride react with β-nitrostyrenes in the presence of three equivalents of MgCl2 under argon.
- Chu, Cheng-Ming,Liu, Ju-Tsung,Lin, Wen-Wei,Yao, Ching-Fa
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- Free-Radical Reactions of Trialkylboranes with β-Nitrostyrenes to Generate Alkenes
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β-Nitrostyrenes 1 react with trialkylboranes under a nitrogen atmosphere to generate high yields of alkenes 2. The mechanism is proposed to be a free-radical reaction via NO2/alkyl substitution since the reaction is stimulated by the presence of a trace of oxygen in the nitrogen or tert-butyl peroxide or by photolysis and is retarded or inhibited by the addition of galvinoxyl to the solution.
- Yao, Ching-Fa,Chu, Cheng-Ming,Liu, Ju-Tsung
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p. 719 - 722
(2007/10/03)
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- An unexpected reaction between 2-aryl-1-nitro-1-alkenes and trialkylgallium compounds
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A novel reaction between 2-aryl-1-nitro-1-alkenes and trialkylgallium compound via NO2/alkyl substitution is found, and a possible mechanism is proposed.
- Han, Ying,Huang, Yao-Zeng,Zhou, Cheng-Ming
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p. 3347 - 3350
(2007/10/03)
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