- Synthesis of Enantioenriched 3,4-Disubstituted Chromans through Lewis Base Catalyzed Carbosulfenylation
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A method for the catalytic, enantioselective, carbosulfenylation of alkenes to construct 3,4-disubstituted chromans is described. Alkene activation proceeds through the intermediacy of enantioenriched, configurationally stable thiiranium ions generated from catalytic, Lewis base activation of an electrophilic sulfenylating agent. The transformation affords difficult-to-generate, enantioenriched, 3,4-disubstituted chromans in moderate to high yields and excellent enantioselectivities. A variety of substituents are compatible including electronically diverse functional groups as well as several functional handles such as aryl halides, esters, anilines, and phenols. The resulting thioether moiety is amenable to a number of functional group manipulations and transformations. Notably, the pendant sulfide was successfully cleaved to furnish a free thiol which readily provides access to most sulfur-containing functional groups which are present in natural products and pharmaceuticals.
- Denmark, Scott E.,Laverny, Aragorn,Menard, Travis
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p. 14290 - 14310
(2021/11/12)
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- Selective Synthesis of Z-Cinnamyl Ethers and Cinnamyl Alcohols through Visible Light-Promoted Photocatalytic E to Z Isomerization
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A photocatalytic E to Z isomerization of alkenes using an iridium photosensitizer under mild reaction conditions is disclosed. This method provides scalable and efficient access to Z-cinnamyl ether and allylic alcohol derivatives in high yields with excellent stereoselectivity. Importantly, this method also provides a powerful strategy for the selective synthesis of Z-magnolol and honokiol derivatives possessing potential biological activity.
- Li, Hengchao,Chen, Hang,Zhou, Yang,Huang, Jin,Yi, Jundan,Zhao, Hongcai,Wang, Wei,Jing, Linhai
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supporting information
p. 555 - 559
(2020/02/05)
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- Cross-coupling reaction of allylic ethers with aryl Grignard reagents catalyzed by a nickel pincer complex
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A cross-coupling reaction of allylic aryl ethers with arylmagnesium reagents was investigated using β-aminoketonato- and β-diketiminato-based pincer-type nickel(II) complexes as catalysts. An β-aminoketonato nickel(II) complex bearing a diphenylphosphino group as a third donor effectively catalyzed the reaction to afford the target cross-coupled products, allylbenzene derivatives, in high yield. The regioselective reaction of a variety of substituted cinnamyl ethers proceeded to give the corresponding linear products. In contrast, α- and γ-alkyl substituted allylic ethers afforded a mixture of the linear and branched products. These results indicated that the coupling reaction proceeded via a π-allyl nickel intermediate.
- Hashimoto, Toru,Funatsu, Kei,Ohtani, Atsufumi,Asano, Erika,Yamaguchi, Yoshitaka
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- Palladium-Catalyzed Aerobic Oxygenation of Allylarenes
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An efficient and practical protocol for the synthesis of (E)-allylethers from readily available olefins with alcohols or phenols was developed. This aerobic oxidative allylic C-H oxygenation protocol features mild conditions, broad substrate scope, and hi
- Li, Chunsheng,Li, Meng,Li, Jianxiao,Liao, Jianhua,Wu, Wanqing,Jiang, Huanfeng
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p. 10912 - 10919
(2017/10/27)
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- Co-Catalyzed Hydroarylation of Unactivated Olefins
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A mild, general, scalable, and functional group tolerant intramolecular hydroarylation of unactivated olefins using a Co(salen) complex, a N-fluoropyridinium salt, and a disiloxane reagent was reported. This method, which was carried out at room temperature, afforded six-membered benzocyclic compounds from mono-, 1,1- or trans-1,2-di, and trisubstituted olefins.
- Shigehisa, Hiroki,Ano, Takuya,Honma, Hiroshi,Ebisawa, Kousuke,Hiroya, Kou
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supporting information
p. 3622 - 3625
(2016/08/16)
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- Polymeric β-alanine incarcerated Pd(ii) catalyzed allylic etherification in water: A mild and efficient method for the formation of C(sp3)-O bonds
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A new heterogeneous palladium(ii) catalyst has been developed through a convenient and economic way. The catalyst was synthesized by confining palladium metal with a polystyrenal β-alanine-imine network and characterized by FT-IR spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X-ray, and elemental analysis. Polymeric imine can be prepared easily from chloromethylated polystyrene and β-alanine. Using this polymer incarcerated palladium(ii) catalyst a useful and efficient procedure for stereospecific synthesis of allyl-aryl ethers has been developed. The benzylic, aromatic, and heteroaromatic phenols react with various substituted allyl acetates by this procedure to furnish a library of allyl-aryl and allyl-hetero-aryl ethers in high yields. The catalyst could be recovered easily and reused five times without any considerable loss of its catalytic activity.
- Halder, Mita,Islam, Md. Mominul,Ahammed, Sabir,Islam, Sk. Manirul
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p. 8282 - 8289
(2016/02/09)
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- An efficient palladium-catalyzed synthesis of cinnamyl ethers from aromatic halides, phenols, and allylic chloride
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A one-pot, two-step catalytic protocol for the preparation of cinnamyl ethers from simple and readily available aryl halides, phenols and allyl chloride is reported for the first time. This simple and highly efficient palladium nanoparticles catalytic system shows good regio- and stereoselectivities and affords the desired products in good to high yields (49-85%) from aryl iodides. Furthermore, less reactive aryl bromides can also give the cinnamyl ethers in moderate yields (24-72%).
- Wang, Wei,Zhou, Rong,Jiang, Zhi-Jie,Wang, Kun,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
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p. 616 - 622
(2014/05/20)
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- From precursor to catalyst: The involvement of [Ru(η5-Cp?)Cl2]2 in highly branch selective allylic etherification of cinnamyl chlorides
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(RuCp?Cl2)2, a general entry into Cp?Ru sandwich and half-sandwich chemistry was first used as a precatalyst in allylic etherification of cinnamyl chlorides with up to 98:2 regioselectivity (19 examples). Both the solvent effect and the exsiccant reaction condition are crucial to the reactivity and selectivity. Preliminary mechanism studies and the demonstration of Fluoxetine synthesis were presented in this work as well.
- Siddappa, Ravi Kumara Guralamatta,Chang, Chih-Wei,Chein, Rong-Jie
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supporting information
p. 1031 - 1035
(2015/02/19)
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- Homogeneous Pd-catalyzed transformation of terminal alkenes into primary allylic alcohols and derivatives
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Synthesis of primary alcohols from terminal alkenes is an important process in both bulk and fine chemical syntheses. Herein, a homogeneous Pd-complex-catalyzed transformation of terminal alkenes into primary allylic alcohols, by using 5 mol % [Pd(PPh3)4] as a catalyst, and H2O, CO2, and quinone derivatives as reagents, is reported. When alcohols were used instead of H2O, allylic ethers were obtained. A proposed mechanism includes the addition of oxygen nucleophiles at the less-hindered terminal position of π-allyl Pd intermediates.
- Tomita, Ren,Mantani, Kohei,Hamasaki, Akiyuki,Ishida, Tamao,Tokunaga, Makoto
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supporting information
p. 9914 - 9917
(2014/08/18)
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- Nickel(0) triethyl phosphite complex-catalyzed allylic substitution with retention of regio- and stereochemistry
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(Chemical Equation Presented) Nickel(0) triethyl phosphite complex-promoted reaction of allylic acetates with thiols produced allylic sulfides with retention of configuration without allylic rearrangement. A similar reaction of allylic acetates with alcohols and phenols also proceeded with retention of regio- and stereochemistry.
- Yatsumonji, Yasutaka,Ishida, Yusuke,Tsubouchi, Akira,Takeda, Takeshi
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p. 4603 - 4606
(2008/03/12)
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- Synthesis and reactivity of complexes 2a-c, their involvement as catalyst precursors for regioselective allylic substitution reactions and related [Ru(Cp*)Cl(Ph2POMe)(RCHCHCH2)] [PF6] η3-allyl ruthenium(IV)inter
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The synthesis of the new complexes [Ru(Cp*)(L)(MeCN) 2]-[PF6] (L = Ph2POMe or Ph2P-o- tolyl) and {Ru(Cp*)-[Ph2PCH2C(tBu)=O](MeCN)}[PF 6] (2a-c) is achieved starting from [Ru(Cp*)
- Demerseman, Bernard,Renaud, Jean-Luc,Toupet, Loic,Hubert, Claudie,Bruneau, Christian
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p. 1371 - 1380
(2007/10/03)
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- Regioselective allylic alkylation and etherification catalyzed by in situ generated N-heterocyclic carbene ruthenium complexes
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Benzimidazolium halides are used for the first time as ligand precursors in ruthenium-catalyzed substitution of allylic carbonates and chlorides by carbon nucleophiles and phenols, respectively. After generation of diaminocarbene species upon deprotonatio
- Gürbüz, Nevin,?zdemir, Ismail,?etinkaya, Bekir,Renaud, Jean-Luc,Demerseman, Bernard,Bruneau, Christian
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p. 535 - 538
(2007/10/03)
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- Practical Pd/C-mediated allylic substitution in water
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Pd/C-mediated allylic substitution in water is described as an interesting alternative to classical homogeneous conditions. The reaction applied to allylic acetates showed a wide range of compatibility with various nitrogen, sulfur, oxygen, and carbon nucleophiles. Notably, the method features inexpensive reagents and a nontoxic solvent. Moreover, measurement of the palladium content in water by ICP-MS shows low palladium contamination (4 ppm) of the solvent, rendering this method safer for the environment compared to homogeneous conditions. The first asymmetric example of Pd/C-mediated allylic substitution is also disclosed.
- Felpin, Francois-Xavier,Landais, Yannick
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p. 6441 - 6446
(2007/10/03)
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- Ruthenium-catalyzed o-allylation of phenols from allylic chlorides via cationic [Cp*(η3-allyl)(MeCN)RuX][PF6] complexes
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The [Cp*(MeCN)3Ru(II)][PF6] complex is an efficient catalyst precursor for the O-allylation of phenols with allylic chlorides in the presence of K2CO3 under mild conditions. This ruthenium precursor affords branched allyl aryl ethers according to a regioselective reaction, which contrasts with the uncatalyzed nucleophilic substitution from the same substrates. Stable (η3-allyl)Ru(IV) cationic complexes resulting from the reaction of [Cp*(MeCN) 3Ru][PF6] with allylic halides were identified as intermediate catalytic species. An X-ray structure determination of the complex [Cp*(MeCHCHCH2)(MeCN)RuBr] [PF6] disclosed an (endo-trans-MeCHCHCH2) allylic ligand. The structural information obtained from the study of Cp*(allyl)Ru(IV) complexes indicated that electronic effects at the coordinated allylic ligand likely account for the better regioselectivity obtained from cinnamyl chloride as compared to aliphatic allylic chlorides.
- Mbaye, Mbaye D.,Demerseman, Bernard,Renaud, Jean-Luc,Toupet, Loic,Bruneau, Christian
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p. 835 - 841
(2007/10/03)
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- First enantioselective allylic etherification with phenols catalyzed by chiral ruthenium bisoxazoline complexes
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Regio- and enantioselective substitution of cinnamyl chloride by phenols has been achieved with up to 82% enantiomeric excess, using a ruthenium catalyst prepared from [Cp*(CH3CN)3Ru] [PF6] and a chiral bisoxazoline ligand.
- Mbaye, Mbaye D.,Renaud, Jean-Luc,Demerseman, Bernard,Bruneau, Christian
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p. 1870 - 1871
(2007/10/03)
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- Palladium-catalyzed coupling of alkynes with alcohols and carboxylic acids
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The palladium-catalyzed coupling of alkynes with alcohols and carboxylic acids to give allylic ethers and esters has been achieved. With phenols, these conditions furnish the C-alkylation products.
- Zhang, Weijiang,Haight, Anthony R.,Hsu, Margaret C.
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p. 6575 - 6578
(2007/10/03)
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