- Visible-Light-Induced Meerwein Fluoroarylation of Styrenes
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An unprecedented approach for assembling a broad range of 1,2-diarylethane derivatives with fluorine-containing fully substituted carbon centers was developed. The protocol features straightforward operation, proceeds under metal-free condition, and accommodates a large variety of synthetically useful functionalities. The critical aspect to the success of this novel transformation lies in using aryldiazonium salts as both aryl radical progenitor and also as single electron acceptor which elegantly enables a radical-polar crossover manifold.
- Tang, Hai-Jun,Zhang, Bin,Xue, Fei,Feng, Chao
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supporting information
p. 4040 - 4044
(2021/05/26)
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- Electrochemistry enabled selective vicinal fluorosulfenylation and fluorosulfoxidation of alkenes
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Both sulfur and fluorine play important roles in organic synthesis, the life science, and materials science. The direct incorporation of these elements into organic scaffolds with precise control of the oxidation states of sulfur moieties is of great significance. Herein, we report the highly selective electrochemical vicinal fluorosulfenylation and fluorosulfoxidation reactions of alkenes, which were enabled by the unique ability of electrochemistry to dial in the potentials on demand. Preliminary mechanistic investigations revealed that the fluorosulfenylation reaction proceeded through a radical-polar crossover mechanism involving a key episulfonium ion intermediate. Subsequent electrochemical oxidation of fluorosulfides to fluorosulfoxides were readily achieved under a higher applied potential with the adventitious H2O in the reaction mixture.
- Jiang, Yimin,Shi, Zhaojiang,Wu, Jinnan,Wu, Shaofen,Ye, Keyin,Yu, Yi,Yuan, Yaofeng
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supporting information
(2021/11/17)
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- An expedient route to tricyanovinylindoles and indolylmaleimides fromo-alkynylanilines utilising DMSO as a one-carbon synthon
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A Pd(ii)/Cu(ii) catalysed domino synthesis of tricyanovinylindoles has been achieved using DMSO as a one-carbon synthon. The reaction proceedsviathe construction of 2-aryl-3-formyl indole followed by sequential addition of malononitrile and a CN resulting
- Chakraborty, Nikita,Dahiya, Anjali,Modi, Anju,Patel, Bhisma K.,Rakshit, Amitava
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supporting information
p. 6847 - 6857
(2021/08/20)
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- Photoredox-Catalyzed Benzylic Esterification via Radical-Polar Crossover
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Photoredox-catalyzed C-O bond formation reactions are reported. The decarboxylative esterification reaction allows the conversion of a variety of arylacetic acids into the corresponding benzyl carboxylates. Furthermore, the use of (diacetoxyiodo)benzene allows the conversion of the benzylic C-H bond through hydrogen atom transfer. The reactions were applied to the divergent transformation of pharmaceuticals via decarboxylative or C-H esterification reactions.
- Maeda, Bumpei,Sakakibara, Yota,Murakami, Kei,Itami, Kenichiro
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supporting information
p. 5113 - 5117
(2021/07/19)
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- Photoredox-Catalyzed α-Aminomethyl Carboxylation of Styrenes with Sodium Glycinates: Synthesis of γ-Amino Acids and γ-Lactams
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A visible-light photoredox-catalyzed reductive α-aminomethyl carboxylation of styrenes with sodium glycinates and CO2 has been developed to synthesize a series of α,α-disubstituted γ-amino acids and γ-lactams with high efficiency and regioselectivity. Notably, CO2 released from the decarboxylation step can be reused for the subsequent carboxylation. Distinct from the previous reactions with the same type of substrates leading to simple decarboxylation and olefin hydroalkylation, this process involves additional CO2 sequestration, thus leading to olefin α-aminomethyl carboxylation. These findings not only provide new access to α,α-disubstituted γ-amino acids and γ-lactams but also serve as a proof of concept for CO2 reutilization in decarboxylation reactions.
- Zhou, Cong,Li, Miao,Sun, Jianwei,Cheng, Jiang,Sun, Song
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supporting information
p. 2895 - 2899
(2021/05/05)
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- Recyclable and reusable PdCl2(PPh3)2/PEG-400/H2O system for the hydrophenylation of alkynes with sodium tetraphenylborate
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A stable and efficient PdCl2(PPh3)2/PEG-400/H2O catalytic system for the hydrophenylation reaction of alkynes has been developed. In the presence of 3 mol% PdCl2(PPh3)2 and 2 equiv. of HOAc, the hydrophenylation of both terminal and internal alkynes with sodium tetraphenylborate proceeded smoothly in a mixture of PEG-400 and water at room temperature or 50 °C to afford a variety of phenyl-substituted alkenes in moderate to high yields. The isolation of the products was easily performed by extraction with petroleum ether, and the PdCl2(PPh3)2/PEG-400/H2O system could be readily recycled and reused six times without apparent loss of catalytic activity.
- Liu, Rong,Zhang, Tingli,Huang, Bin,Cai, Mingzhong
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p. 172 - 178
(2020/07/04)
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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.
- -
-
Paragraph 0060-0069; 0094
(2021/02/10)
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- 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.
- -
-
Paragraph 0053-0054; 0057-0062; 0078
(2021/02/10)
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- Bromomethyl Silicate: A Robust Methylene Transfer Reagent for Radical-Polar Crossover Cyclopropanation of Alkenes
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A general protocol for visible-light-induced cyclopropanation of alkenes was developed with bromomethyl silicate as a methylene transfer reagent, offering a robust tool for accessing highly valuable cyclopropanes. In addition to α-aryl or methyl-substituted Michael acceptors and styrene derivatives, the unactivated 1,1-dialkyl ethylenes were also shown to be viable substrates. Apart from realizing the cyclopropanation of terminal alkenes, the methyl transfer reaction has been further demonstrated to be amenable to the internal olefins. The photocatalytic cyclopropanation of 1,3-bis(1-arylethenyl)benzenes was also achieved, giving polycyclopropane derivatives in excellent yields. With late-stage cyclopropanation as the key strategy, the synthetic utility of this transformation was also demonstrated by the total synthesis of LG100268.
- Luo, Wenping,Fang, Yewen,Zhang, Li,Xu, Tianhang,Liu, Yongjun,Li, Yan,Jin, Xiaoping,Bao, Jiakan,Wu, Xiaodong,Zhang, Zongyong
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supporting information
p. 1778 - 1781
(2020/03/11)
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- Spiro[1,2]oxaphosphetanes of nonstabilized and semistabilized phosphorus ylide derivatives: Synthesis and kinetic and computational study of their thermolysis
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A series of tri- and tetrasubstituted spiro-oxaphosphetanes stabilized by ortho-benzamide (oBA) and N-methyl ortho-benzamide (MoBA) ligands have been synthesized by the reaction of Cα,Cortho-dilithiated phosphazenes with aldehydes and ketones. They include enantiopure products and the first example of an isolated oxaphosphetane having a phenyl substituent at C3 of the ring. Kinetic studies of their thermal decomposition showed that the process takes place irreversibly through a polar transition state (ρ = -0.22) under the influence of electronic, [1,2], [1,3] steric, and solvent effects, with C3/P-[1,2] interactions as the largest contribution to ΔG of olefination. Inversion of the phosphorus configuration through stereomutation has been observed in a number of cases. DFT calculations showed that oBA derivatives olefinated through the isolated (N, O)(Ph, C6H4, C) oxaphosphetanes (Channel A), whereas MoBA compounds decomposed faster via the isomer (C6H4, O)(C, N, Ph) formed by P-stereomutation involving a MB2 permutational mechanism (Channel B). The energy barrier of P-isomerization is lower than that of olefination. Fragmentation takes place in a concerted asynchronous reaction. The thermal stability of oxaphosphetanes is determined by strong C3/P-[1,2] interactions destabilizing the transition state of olefination. The effect of charge distribution and C3/C4-[1,2] and C4/P-[1,3] steric and solvent interactions on ΔG was also evaluated.
- López, Jesús García,Sansores Peraza, Pablo M.,Iglesias, María José,Roces, Laura,García-Granda, Santiago,Ortiz, Fernando López
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p. 14570 - 14591
(2020/11/20)
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- Cu/Ni-Catalyzed Cyanomethylation of Alkenes with Acetonitrile for the Synthesis of β,γ-Unsaturated Nitriles
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We have developed a protocol for the Cu/Ni-catalyzed cyanomethylation of alkenes with acetonitrile for the synthesis of β,γ-unsaturated nitriles. This is the first example of a direct coupling of the alkene sp2 C - H bond and the acetonitrile sp3 C - H bond for the preparation of β,γ-unsaturated nitriles. Acetonitrile, an inexpensive and stable solvent, is demonstrated to be a useful cyanomethyl source. The combination of copper and nickel catalysts resulted in a high reaction efficiency.
- Jian, Hong,Shen, Zengming,Zhang, Saisai
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supporting information
p. 6143 - 6150
(2020/05/22)
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- Intermolecular Carbonyl–olefin Metathesis with Vinyl Ethers Catalyzed by Homogeneous and Solid Acids in Flow
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The carbonyl–olefin metathesis reaction has experienced significant advances in the last seven years with new catalysts and reaction protocols. However, most of these procedures involve soluble catalysts for intramolecular reactions in batch. Herein, we show that recoverable, inexpensive, easy to handle, non-toxic, and widely available simple solid acids, such as the aluminosilicate montmorillonite, can catalyze the intermolecular carbonyl–olefin metathesis of aromatic ketones and aldehydes with vinyl ethers in-flow, to give alkenes with complete trans stereoselectivity on multi-gram scale and high yields. Experimental and computational data support a mechanism based on a carbocation-induced Grob fragmentation. These results open the way for the industrial implementation of carbonyl–olefin metathesis over solid catalysts in continuous mode, which is still the origin and main application of the parent alkene–alkene cross-metathesis.
- Cerón-Carrasco, José Pedro,Leyva-Pérez, Antonio,Pérez-Sánchez, Horacio,Rivero-Crespo, Miguel ángel,Tejeda-Serrano, María
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supporting information
p. 3846 - 3849
(2019/11/11)
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- Peroxide-mediated site-specific C-H methylation of imidazo[1,2-: A] pyridines and quinoxalin-2(1 H)-ones under metal-free conditions
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An effective approach to realize the direct methylation of imidazo[1,2-a]pyridines and quinoxalin-2(1H)-ones with peroxides under metal-free conditions is described. In this protocol, peroxides serve as both the radical initiator and methyl source. Methylated imidazopyridines and quinoxalin-2(1H)-ones were smoothly synthesized in moderate to good yields. A free radical reaction mechanism was proposed to describe the methylation process.
- Jin, Shengzhou,Yao, Hua,Lin, Sen,You, Xiaoqing,Yang, Yao,Yan, Zhaohua
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supporting information
p. 205 - 210
(2020/01/13)
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- Regioselective Diboron-Mediated Semireduction of Terminal Allenes
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A method for the regioselective reduction of the terminal double bond of 1,1-disubstituted allenes has been developed. In the presence of a palladium catalyst, tetrahydroxydiboron and stoichiometric water, allene semireduction proceeds in high yield to afford Z-alkenes selectively.
- Gates, Ashley M.,Santos, Webster L.
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p. 4619 - 4624
(2019/12/11)
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- The Cascade Methylation/Cyclization of ortho-Cyanoarylacrylamides with Dicumyl Peroxide
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A radical cascade methylation/cyclization of ortho-cyanoarylacrylamides was developed by utilizing dicumyl peroxide as a methylation reagent. This transformation provides a simple and straightforward approach to methylated quinoline-2,4(1H,3H)-diones, and
- Yang, Tao,Xia, Wen-Jin,Zhou, Bin,Xin, Yangchun,Shen, Yuehai,Li, Ya-Min
-
supporting information
p. 5749 - 5755
(2019/08/26)
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- Conversion of Carbonyl Compounds to Olefins via Enolate Intermediate
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A general and efficient protocol to synthesize substituted olefins from carbonyl compounds via nickel catalyzed C—O activation of enolates was developed. Besides ketones, aldehydes were also suitable substrates for the presented catalytic system to produce di- or tri- substituted olefins. It is worth noting that this approach exhibited good tolerance to highly reactive tertiary alcohols, which could not survive in other reported routes for converting carbonyl compounds to olefins. This method also showed good regio- and stereo-selectivity for olefin products. Preliminary mechanistic studies indicated that the reaction was accomplished through nickel catalyzed C—O activation of enolates, thus offering helpful contribution to current enol chemistry.
- Cao, Zhi-Chao,Xu, Pei-Lin,Luo, Qin-Yu,Li, Xiao-Lei,Yu, Da-Gang,Fang, Huayi,Shi, Zhang-Jie
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supporting information
p. 781 - 785
(2019/06/24)
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- Employing Water as the Hydride Source in Synthesis: A Case Study of Diboron Mediated Alkyne Hydroarylation
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We present an approach to utilize water as the hydride source via Pd(II)/Pd(0) catalysis. As a case study, we have achieved a diboron mediated Pd(II)-catalyzed hydroarylation of alkynes using arylboronic acids. This approach not only complements conventional reactivity of Pd via Pd(0)/Pd(II) cycle for the hydroarylation but also utilizes water as the hydride source. We believe this would particularly be beneficial in utilizing water as a reagent.
- Rao, Santhosh,Joy, M. Nibin,Prabhu, Kandikere Ramaiah
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p. 13707 - 13715
(2018/11/30)
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- Hydrodebromination of allylic and benzylic bromides with water catalyzed by a rhodium porphyrin complex
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Hydrodebromination of allylic and benzylic bromides was successfully achieved by a rhodium porphyrin complex catalyst using water as the hydrogen source without a sacrificial reductant. Mechanistic investigations suggest that bromine atom abstraction via a rhodium porphyrin metalloradical operates to give the rhodium porphyrin alkyl species and the subsequent hydrolysis of the rhodium porphyrin alkyl species to a hydrocarbon product is a key step to harness the hydrogen from water.
- Yang, Wu,Chen, Chen,Chan, Kin Shing
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p. 12879 - 12883
(2018/10/02)
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- Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
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Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
- Jereb, Marjan,Vra?i?, Dejan
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p. 747 - 762
(2018/01/17)
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- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
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An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
-
supporting information
p. 12634 - 12637
(2017/12/02)
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- Ruthenium(II)-catalyzed olefination: Via carbonyl reductive cross-coupling
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Natural availability of carbonyl groups offers reductive carbonyl coupling tremendous synthetic potential for efficient olefin synthesis, yet the catalytic carbonyl cross-coupling remains largely elusive. We report herein such a reaction, mediated by hydrazine under ruthenium(ii) catalysis. This method enables facile and selective cross-couplings of two unsymmetrical carbonyl compounds in either an intermolecular or intramolecular fashion. Moreover, this chemistry accommodates a variety of substrates, proceeds under mild reaction conditions with good functional group tolerance, and generates stoichiometric benign byproducts. Importantly, the coexistence of KOtBu and bidentate phosphine dmpe is vital to this transformation.
- Wei, Wei,Dai, Xi-Jie,Wang, Haining,Li, Chenchen,Yang, Xiaobo,Li, Chao-Jun
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p. 8193 - 8197
(2017/11/27)
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- Copper-Catalyzed Hydroarylation of Internal Alkynes: Highly Regio- and Diastereoselective Synthesis of 1,1-Diaryl, Trisubstituted Olefins
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The copper-catalyzed hydroarylation of internal, unsymmeric alkynes is presented. Trisubstituted alkenes are obtained as single diastereomers in good to excellent yields and excellent regioselectivities. The scope of the reaction is presented with respect to alkyne and aryl iodide coupling partners. Initial mechanistic experiments indicate a hydrocupration event followed by a two-electron oxidative addition/reductive elimination pathway.
- Kortman, Gregory D.,Hull, Kami L.
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p. 6220 - 6224
(2017/09/15)
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- Selective Pd-catalyzed hydrogenation of 3,3-diphenylallyl alcohol: Efficient synthesis of 3,3-diarylpropylamine drugs diisopromine and feniprane
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The Pd-catalyzed selective hydrogenation of C[dbnd]C double bond in (3,3-diphenylallyl)diisopropylamine or 3,3-diphenylallyl alcohol was evaluated using different catalytic systems [Pd/C, Pd(OAc)2/ionic liquid, isolated Pd(0) nanoparticles]. For the (3,3-diphenylallyl)diisopropylamine, hydrogenolysis is preferred over hydrogenation, and only moderate selectivities were obtained for the desired product. However, complete conversion and 100% selectivity were obtained for the hydrogenation of 3,3-diphenylallyl alcohol using isolated Pd(0) nanoparticles under mild condition. This successful strategy enabled the effective synthesis of diisopromine and feniprane drugs and opens new possibilities for the preparation of other biologically active compounds.
- Claudino, Thiago S.,Scholten, Jackson D.,Monteiro, Adriano L.
-
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- Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions
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Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.
- Lei, Chuanhu,Yip, Yong Jie,Zhou, Jianrong Steve
-
supporting information
p. 6086 - 6089
(2017/05/08)
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- Doubly Regioselective C-H Hydroarylation of Unsymmetrical Alkynes Using Carboxylates as Deciduous Directing Groups
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A catalyst system composed of [(C6Me6)RuCl2]2, potassium carbonate/guanidine carbonate, and mesitoic acid efficiently promotes the doubly regioselective C-H hydroarylation of unsymmetrical alkynes. The process involves carboxylate-directed ortho-C-H bond activation followed by regioselective addition to the alkyne C-C triple bond with concerted decarboxylation. This action of the carboxylate as a deciduous directing group ensures exclusive monovinylation with high selectivity for the (E)-1,2-diarylalkene.
- Biafora, Agostino,Khan, Bilal A.,Bahri, Janet,Hewer, Joachim M.,Goossen, Lukas J.
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supporting information
p. 1232 - 1235
(2017/03/14)
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- Synthesis method for flavonoid compound drug intermediate 1,1-diphenyl-1-propylene
-
The invention provides a synthesis method for a flavonoid compound drug intermediate 1,1-diphenyl-1-propylene. The synthesis method comprises the following steps that 3.6 mol of 1,1-diphenyl-1-propanol, 350 ml of a hypochlorous acid solution, 3.9-4.2 mol
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-
Paragraph 0006; 0014-0015
(2017/03/08)
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- Enantioselective Oxidative Rearrangements with Chiral Hypervalent Iodine Reagents
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A stereoselective hypervalent iodine-promoted oxidative rearrangement of 1,1-disubstituted alkenes has been developed. This practically simple protocol provides access to enantioenriched α-arylated ketones without the use of transition metals from readily
- Brown, Michael,Kumar, Ravi,Rehbein, Julia,Wirth, Thomas
-
supporting information
p. 4030 - 4035
(2016/03/16)
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- Preparation of polycyclic compounds by intramolecular photospirocyclization and photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives
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Photoreactions of 4-pentenyl-1-cyanonaphthalenes yield spirocyclic products along with [4?+?2] cycloadducts. Photoreactions of 5-phenyl derivatives produce a product having tricyclo[6.3.0.01,4]undecadiene skeleton. Formation of angular triquinanes takes place in photoreactions of cycloalkene-linked cyanonaphthalenes. The observation demonstrates that π–π arene ring interactions, steric hindrance, and suitable locations of reaction sites in syn and anti singlet exciplexes govern the modes followed in intramolecular photoreactions of 4-alkenyl-1-cyanonaphthalenes.
- Maeda, Hajime,Wada, Hidenori,Mukae, Hirofumi,Mizuno, Kazuhiko
-
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- Iron-Catalyzed Ortho C-H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand
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Iron-catalyzed C-H functionalization of aromatics has attracted widespread attention from chemists in recent years, while the requirement of an elaborate directing group on the substrate has so far hampered the use of simple aromatic carbonyl compounds such as benzoic acid and ketones, much reducing its synthetic utility. We describe here a combination of a mildly reactive methylaluminum reagent and a new tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphanyl)-N,N-dimethylaniline (Me2N-TP), that allows us to convert an ortho C-H bond to a C-CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C-H bonds in benzophenone. The reaction tolerates a variety of functional groups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones.
- Shang, Rui,Ilies, Laurean,Nakamura, Eiichi
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supporting information
p. 10132 - 10135
(2016/08/31)
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- Metal-free oxidative cross-coupling of diazirines with arylboronic acids
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We report herein a metal-free cross-coupling of diazirines with arylboronic acids under oxidative conditions. The reaction affords a series of substituted olefins. It is proposed that the interaction between the nitrogen on diazirine with arylboronic acid plays a key role in this transformation.
- Wu, Guojiao,Zhao, Xia,Ji, Wenzhi,Zhang, Yan,Wang, Jianbo
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p. 1961 - 1963
(2016/02/05)
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- Copper(I)-Catalyzed Allylic Substitutions with a Hydride Nucleophile
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An easily accessible copper(I)/N-heterocyclic carbene (NHC) complex enables a regioselective hydride transfer to allylic bromides, an allylic reduction. The resulting aryl- and alkyl-substituted branched α-olefins, which are valuable building blocks for synthesis, are obtained in good yields and regioselectivity. A commercially available silane, (TMSO)2Si(Me)H, is employed as hydride source. This protocol offers a unified alternative to the established metal-catalyzed allylic substitutions with carbon nucleophiles, as no adaption of the catalyst to the nature of the nucleophile is required.
- Nguyen, T. N. Thanh,Thiel, Niklas O.,Pape, Felix,Teichert, Johannes F.
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supporting information
p. 2455 - 2458
(2016/06/09)
-
- Ethers as hydrogen sources in BF3·OEt2 promoted reduction of diphenylmethyl alcohols, ethers and esters to hydrocarbons
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A novel ether/BF3 reductive system has been described, in which diphenylmethanols and their ether and ester derivatives are used as starting materials. Reductions are performed in ether under reflux and an argon atmosphere, and the addition of extra water is beneficial to this reduction. A series of alkanes are able to be prepared with good to excellent yields. A deuterated experiment exhibits that the reductive hydrogen is generated from ether. The mechanism is discussed in detail to explain the observed reactivity.
- Li, Jiaqiang,Liu, Qing,Shen, Hang,Huang, Ruofeng,Zhang, Xiaohui,Xiong, Yan,Chen, Changguo
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p. 85291 - 85295
(2015/11/02)
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- Biphilic organophosphorus catalysis: Regioselective reductive transposition of allylic bromides via PIII/PV redox cycling
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We report that a regioselective reductive transposition of primary allylic bromides is catalyzed by a biphilic organophosphorus (phosphetane) catalyst. Spectroscopic evidence supports the formation of a pentacoordinate (σ5-P) hydridophosphorane as a key reactive intermediate. Kinetics experiments and computational modeling are consistent with a unimolecular decomposition of the σ5-P hydridophosphorane via a concerted cyclic transition structure that delivers the observed allylic transposition and completes a novel PIII/PV redox catalytic cycle. These results broaden the growing repertoire of reactions catalyzed within the PIII/PV redox couple and suggest additional opportunities for organophosphorus catalysis in a biphilic mode.
- Reichl, Kyle D.,Dunn, Nicole L.,Fastuca, Nicholas J.,Radosevich, Alexander T.
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supporting information
p. 5292 - 5295
(2015/05/13)
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- Direct C-H trifluoromethylation of di- and trisubstituted alkenes by photoredox catalysis
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Background: Trifluoromethylated alkene scaffolds are known as useful structural motifs in pharmaceuticals and agrochemicals as well as functional organic materials. But reported synthetic methods usually require multiple synthetic steps and/or exhibit lim
- Tomita, Ren,Yasu, Yusuke,Koike, Takashi,Akita, Munetaka
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supporting information
p. 1099 - 1106
(2014/06/09)
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- Iron-catalyzed decarboxylative methylation of α,β-unsaturated acids under ligand-free conditions
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It is the first time to find that iron-catalyzed decarboxylative methylation of α,β-unsaturated acids could be performed in the absence of any ligands. During the reaction, the configuration of the double bond could be retained. It is noteworthy that di-t
- Rong, Guangwei,Liu, Defu,Lu, Linhua,Yan, Hong,Zheng, Yang,Chen, Jie,Mao, Jincheng
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p. 5033 - 5037
(2014/12/10)
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- Iron-catalyzed decarboxylative methylation of α,β-unsaturated acids under ligand-free conditions
-
It is the first time to find that iron-catalyzed decarboxylative methylation of α,β-unsaturated acids could be performed in the absence of any ligands. During the reaction, the configuration of the double bond could be retained. It is noteworthy that di-t
- Rong, Guangwei,Liu, Defu,Lu, Linhua,Yan, Hong,Zheng, Yang,Chen, Jie,Mao, Jincheng
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p. 5033 - 5037
(2014/07/08)
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- Oxidative heck arylation for the stereoselective synthesis of tetrasubstituted olefins using nitroxides as oxidants
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One, two, and three! Nitroxides and dioxygen serve as oxidants in highly stereoselective oxidative Pd-catalyzed Heck arylations in which aryl boronic acids are used to synthesize triarylalkyl-substituted olefins. The reactions occur under very mild conditions at room temperature. As an example, the threefold sequential arylation of methyl acrylate is the crucial step in the stereoselective synthesis of Z-Tamoxifen.
- He, Zhiheng,Kirchberg, Sylvia,Froehlich, Roland,Studer, Armido
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supporting information; experimental part
p. 3699 - 3702
(2012/05/20)
-
- Manganese(III)-assisted specific intramolecular addition
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Oligomethylene-tethered -alkenyl 3-oxobutanoates and 3-oxobutanamides underwent manganese(III)-mediated oxidative intramolecular addition to produce dihydrofuran-fused macrolides and macrocyclic amides from 8 to 26 members. A similar reaction of the oligooxamethylene-tethered -alkenyl 3-oxobutanoates also gave dihydrofuran-fused crown ether type macrolides which had a phase-transfer ability with sodium and potassium picrates. The manganese(III)-assisted specific intramolecular addition could be explained by the -complexation of the -alkenyl part with the manganese(III) enolate. Georg Thieme Verlag Stuttgart - New York.
- Ito, Yosuke,Jogo, Shunsuke,Fukuda, Noriko,Okumura, Ryo,Nishino, Hiroshi
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experimental part
p. 1365 - 1374
(2011/06/17)
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- Pd-catalyzed oxidative cross-coupling of N-tosylhydrazones with arylboronic acids
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The Pd-catalyzed reaction of N-tosylhydrazones and arylboronic acids provides olefin derivatives. This oxidative cross-coupling is suggested to proceed through a migratory insertion process of a Pd carbene intermediate.
- Zhao, Xia,Jing, Jing,Lu, Kui,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 1724 - 1726
(2010/07/06)
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- The nitrile functionality as a directing group in the Palladium-catalysed addition of aryl boronic acids to alkynes
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The nitrile group is shown to direct the palladium-catalysed hydroarylation of internal alkynes bearing a pendant nitrile with boronic acids.
- Rodriguez, Arantxa,Moran, Wesley J.
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experimental part
p. 7 - 10
(2010/08/20)
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- Microwave-assisted, Pd(0)-catalyzed cross-coupling of diazirines with aryl halides
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Pd(0)-catalyzed cross-coupling reactions of diazirines with aryl halides under microwave heating conditions afford a series of substituted olefins. A reaction mechanism involving the migratory insertion of the Pd carbene intermediate is proposed.
- Zhao, Xia,Wu, Guojiao,Yan, Chong,Lu, Kui,Li, Hui,Zhang, Yan,Wang, Jianbo
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supporting information; experimental part
p. 5580 - 5583
(2011/02/23)
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- Cobalt-catalyzed arylzincation of alkynes
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Cobalt(II) bromide catalyzes arylzincation of alkynes with arylzinc iodide·lithium chloride complexes in acetonitrile. The scope of the arylzincation is wide enough to use unfunctionalized alkynes, such as 6-dodecyne, as well as arylacetylenes. The inherent functional group compatibility of arylzinc reagents allows preparation of various functionalized styrene derivatives. The reaction is applicable to the efficient and stereoselective synthesis of a synthetic estrogen and its derivative.
- Murakami, Kei,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 2373 - 2375
(2009/12/01)
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- Reactions of diazo compounds with alkenes catalysed by [RuCl(cod)(Cp)]: Effect of the substituents in the formation of cyclopropanation or metathesis products
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The reaction of diazo compounds with alkenes catalysed by complex [RuCl(COd)(Cp)] (cod = 1, 5-cyclooctadiene, Cp = cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp)I=C(R1)R 2)] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru-carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N2=C(R 1)R2 (R1, R2 = Ph, H; Ph, CO 2Me; Ph, Ph; C(R1)R2 = fluorene) and the olefin substrates R3(H)C= C(H)R4 (R3, R4 = CO2Et, CO2Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron-poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl.
- Basato, Marino,Tubaro, Cristina,Biffis, Andrea,Bonato, Marco,Buscemi, Gabriella,Lighezzolo, Filippo,Lunardi, Pamela,Yianini, Chiara,Benetollo, Franco,Del Zotto, Alessandro
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experimental part
p. 1516 - 1526
(2009/09/04)
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- First cross-coupling reaction of potassium aryltrifluoroborates with organic chlorides in aqueous media catalyzed by an oxime-derived palladacycle
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(Chemical Equation Presented) Potassium aryltrifluoroborates are cross-coupled with aryl and heteroaryl chlorides using a 4-hydroxyacetophenone oxime-derived palladacycle as precatalyst, K2CO3 as base, and TBAB as additive in refluxing water under conventional and microwave heating affording the corresponding biphenyls under phosphine-free conditions. For the arylation of allyl and benzyl chlorides, KOH is used as base in acetone-water (3:2) at rt or 50 °C using 0.1 mol % Pd loading providing allylbenzenes and diarylmethanes, respectively.
- Alacid, Emilio,Najera, Carmen
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supporting information; scheme or table
p. 5011 - 5014
(2009/05/31)
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- Structural optimization of enantiopure 2-cyclialkylamino-2-aryl-1,1- diphenylethanols as catalytic ligands for enantioselective additions to aldehydes
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(Chemical Equation Presented) The structural optimization of a family of modular, enantiopure β-amino alcohol ligands with a common 2-amino-2-aryl-1,1-diphenylethanol skeleton, whose stereogenicity was introduced through the Jacobsen epoxidation of 1,1-diphenyl-2-arylethylenes, has led to the identification of a small set of optimal catalysts with enhanced activity and enantioselectivity in the addition of alkylzinc and arylzinc reagents to aldehydes. Criteria for the discrimination between apparently analogous, highly enantioselective ligands are proposed.
- Rodriguez-Escrich, Sergi,Reddy, Katamreddy Subba,Jimeno, Ciril,Colet, Gisela,Rodriguez-Escrich, Carles,Sola, Lluis,Vidal-Ferran, Anton,Pericas, Miquel A.
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p. 5340 - 5353
(2008/12/20)
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- Palladium-catalyzed hydrophenylation of alkynes with sodium tetraphenylborate under mild conditions
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(Chemical Equation Presented) In an aqueous solution of acetic acid, PdCl2(PPh3)2 showed high catalytic activity for the hydrophenylation of both terminal and internal alkynes with sodium tetraphenylborate (NaBPh4) under mild conditions, affording phenyl alkenes in moderate to excellent yields.
- Zeng, Hanxiang,Hua, Ruimao
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p. 558 - 562
(2008/09/17)
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- Metal triflate-catalyzed regio- And stereoselective friedelCrafts alkenylation of arenes with alkynes in an ionic liquid: Scope and mechanism
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In the metal triflate-catalyzed hydroarylation of alkynes, employing an ionic liquid dramatically enhanced the catalytic activities, resulting in broadening the scope of substrates (arenes and alkynes). In some cases, even reactions that were not possible in conventional organic solvents proceeded smoothly in ionic liquids. Moreover, the ionic liquid phase containing catalyst could be readily recovered by simple decantation of the organic layer after reaction and reused for the following runs without any significant loss of activity. Mechanistic studies including 13C NMR analysis of reaction intermediates and isotope experiments confirmed for the first time that this type of reaction proceeds via vinyl cationic intermediates.
- Yoon, Mi Young,Kim, Jin Hong,Choi, Doo Seoung,Shin, Ueon Sang,Lee, Jin Yong,Song, Choong Eui
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p. 1725 - 1737
(2008/02/11)
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- A novel (2,2-diarylvinyl)phosphine/palladium catalyst for effective aromatic amination
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A new series of diarylvinylphosphine ligands was designed and synthesized. A catalyst system, consisting of the ligands and palladium species, effectively catalyzed the coupling reaction of aryl bromides and chlorides with amines to afford the corresponding products in good to excellent yields. The efficiency is likely derived from an interaction between the palladium center and the cisaryl moiety on the diarylvinylphosphine ligand stabilizing a catalytic intermediate during the coupling reaction.
- Suzuki, Ken,Hori, Yoji,Nishikawa, Takenobu,Kobayashi, Tohru
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p. 2089 - 2091
(2008/09/18)
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- Iron-promoted elimination of β-thioalkoxy alcohols. Olefination by coupling of a carbonyl group with a dithioacetal
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Treatment of propargylic dithiolanes with nBuLi followed by a carbonyl electrophile yields the corresponding propargylic dithioacetals. Upon treatment with 1 equiv of Fe(BCaC)3 and excess MeMgl, elimination of SR and OH moieties from 8 affords the corresponding olefins in satisfactory yield. Benzylic dithioacetals behave similarly. The reaction can be considered an alternative of McMurry coupling of two different carbonyl equivalents.
- Huang, Li-Fu,Chen, Chih-Wei,Luh, Tien-Yau
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p. 3663 - 3665
(2008/02/12)
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- Dramatic enhancement of catalytic activity in an ionic liquid: Highly practical Friedel-Crafts alkenylation of arenes with alkynes catalyzed by metal triflates
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A simple and highly efficient method for the Friedel-Crafts alkenylation of aromatic compounds has been developed by using a metal triflate (OTf) catalyst in an ionic liquid (see scheme, bmim = 1-butyl-3-methylimidazolium). Not only is the catalytic activity significantly enhanced in the ionic liquid and by-product formation decreased, but some reactions that were not possible in conventional organic solvents were shown to proceed smoothly.
- Song, Choong Eui,Jung, Da-Un,Choung, Su Yhen,Roh, Eun Joo,Lee, Sang-Gi
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p. 6183 - 6185
(2007/10/03)
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