- Allylic Substitution Catalyzed by a New Molybdenum Complex
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A new molybdenum(II) complex (E), generated in situ from Mo(CO)6 by sequential treatment with PhCH2(Et)3N+Cl- and CF3SO3Ag (3 equiv.), has been found to catalyze the substitution of allylic acetates with MeOH (4 -> 5 8; 9
- Dvorakova, Hana,Dvorak, Dalimil,Srogl, Jiri,Kocovsky, Pavel
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- Nickel-Mediated Enantiospecific Silylation via Benzylic C-OMe Bond Cleavage
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Benzylic stereocenters are found in bioactive and drug molecules, as enantiopure benzylic alcohols have been used to build such a stereogenic center, but are limited to the construction of a C-C bond. Silylation of alkyl alcohols has the potential to build bioactive molecules and building blocks; however, the development of such a process is challenging and unknown. Herein, we describe an unprecedented AgF-assisted nickel catalysis in the enantiospecific silylation of benzylic ethers.
- Balakrishnan, Venkadesh,Murugesan, Vetrivelan,Chindan, Bincy,Rasappan, Ramesh
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p. 1333 - 1338
(2021/02/20)
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- Nickel-Catalyzed Arylation of C(sp3)-O Bonds in Allylic Alkyl Ethers with Organoboron Compounds
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A nickel-catalyzed cross-coupling of allylic alkyl ethers with organoboron compounds through the cleavage of the inert C(sp3)-O(alkyl) bonds is described. Several types of allylic alkyl ethers can be coupled with various boronic acids or their derivatives to give the corresponding products in good to excellent yields with wide functional group tolerance and excellent regioselectivity. The gram-scale reaction and late-stage modification of biologically active compounds further prove the practicality of this synthetic method.
- Li, Xiaowei,Li, Yuxiu,Zhang, Zhong,Shi, Xiaolin,Liu, Ruihua,Wang, Zemin,Li, Xiangqian,Shi, Dayong
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supporting information
p. 6612 - 6616
(2021/09/02)
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- Stereoselective synthesis of allyl ethers using α,β-unsaturated acylsilanes
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The reaction behavior of silylvinylmethanols with acid catalysts was investigated. The starting silylvinylmethanols 2 were prepared by the reaction of the corresponding α,β-unsaturated acylsilanes 1 with organocerium reagents. The reaction of 2 with TsOH
- Honda, Mitsunori,Takatera, Takehide,Ui, Ryosuke,Kunimoto, Ko-Ki,Segi, Masahito
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p. 864 - 869
(2017/02/18)
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- Oxidative cleavage of allyl ethers by an oxoammonium salt
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A method to oxidatively cleave allyl ethers to their corresponding aldehydes mediated by an oxoammonium salt is described. Using a biphasic solvent system and mild heating, cleavage proceeds readily, furnishing a variety of α,β-unsaturated aldehydes and ketones.
- Kelly, Christopher B.,Ovian, John M.,Cywar, Robin M.,Gosselin, Taylor R.,Wiles, Rebecca J.,Leadbeater, Nicholas E.
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p. 4255 - 4259
(2015/04/14)
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- Pincer-Nickel-Catalyzed Allyl-Aryl Coupling between Allyl Methyl Ethers and Arylzinc Chlorides
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The P,N,N-pincer nickel complex [Ni(Cl){N(2-Ph2PC6H4)(2′-Me2NC6H4)}]-catalyzed allyl-aryl coupling was studied. The reaction of allyl methyl ethers, including (1-methoxyallyl)arenes and (3-methoxyprop-1-en-1-yl)arenes, with arylzinc chlorides afforded linear (E)-alkenes in high yields, whereas the reaction of (E)-1-methoxytridec-2-ene with p-Me2NC6H4ZnCl generated a mixture of linear and branched alkenes.
- Tao, Jian-Long,Yang, Bo,Wang, Zhong-Xia
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p. 12627 - 12634
(2016/01/09)
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- Chemoselective and direct functionalization of methyl benzyl ethers and unsymmetrical dibenzyl ethers by using iron trichloride
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Methyl and benzyl ethers are widely utilized as protected alcohols due to their chemical stability, such as the low reactivity of the methoxy and benzyloxy groups as leaving groups under nucleophilic conditions. We have established the direct azidation of chemically stable methyl and benzyl ethers derived from secondary and tertiary benzyl alcohols. The present azidation chemoselectively proceeds at the secondary or tertiary benzylic positions of methyl benzyl ethers or unsymmetrical dibenzyl ethers and is also applicable to direct allylation, alkynylation, and cyanation reactions, as well as the azidation. The present methodologies provide not only a novel chemoselectivity but also the advantage of shortened synthetic steps, due to the direct process without the deprotection of the methyl and benzyl ethers. Ethers exchanged: Methyl and benzyl ethers are chemically stable and generally tolerant under nucleophilic substitution conditions. Iron-catalyzed direct functionalizations (e.g., azidation, allylation, alkynylation, and cyanation) of methyl and benzyl ethers derived from secondary and tertiary benzyl alcohols were established with excellent regioselectivities (see scheme; PG: protecting group; Bn: benzyl; Nu: nucleophile; TMS: trimethylsilyl). Copyright
- Sawama, Yoshinari,Goto, Ryota,Nagata, Saori,Shishido, Yuko,Monguchi, Yasunari,Sajiki, Hironao
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supporting information
p. 2631 - 2636
(2014/03/21)
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- Efficient assembly of α-aryl and α-vinyl nitriles via iron-catalyzed ether bond activation
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A novel and practical method for the synthesis of diverse α-aryl and α-vinyl nitriles was developed via an iron-catalyzed sp3 C-O ether bond cleavage with C-C bond formation in the reaction of π-activated ethers with TMSCN.
- Fan, Xiaohui,Guo, Kun,Guan, Yong-Hong,Fu, Lin-An,Cui, Xiao-Meng,Lv, Hao,Zhu, Hong-Bo
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supporting information
p. 1068 - 1071
(2014/02/14)
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- Efficient assembly of α-aryl and α-vinyl nitriles via iron-catalyzed ether bond activation
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A novel and practical method for the synthesis of diverse α-aryl and α-vinyl nitriles was developed via an iron-catalyzed sp3 C-O ether bond cleavage with C-C bond formation in the reaction of π-activated ethers with TMSCN.
- Fan, Xiaohui,Guo, Kun,Guan, Yong-Hong,Fu, Lin-An,Cui, Xiao-Meng,Lv, Hao,Zhu, Hong-Bo
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supporting information
p. 1068 - 1071
(2015/02/18)
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- Iron-catalyzed N-alkylation using π-activated ethers as electrophiles
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A new method for the synthesis of diverse N-alkylation compounds was developed via an iron-catalyzed etheric Csp3-O cleavage with the C-N bond formation in the reaction of π-activated ethers with various nitrogen-based nucleophiles. In addition, the mechanism of this reaction was investigated. The Royal Society of Chemistry 2013.
- Fan, Xiaohui,Fu, Lin-An,Li, Na,Lv, Hao,Cui, Xiao-Meng,Qi, Yuan
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supporting information
p. 2147 - 2153
(2013/04/10)
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- Effects of phosphorus substituents on reactions of α- alkoxyphosphonium salts with nucleophiles
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The effects of phosphorus substituents on the reactivity of α-alkoxyphosphonium salts with nucleophiles has been explored. Reactions of α-alkoxyphosphonium salts, prepared from various acetals and tris(o-tolyl)phosphine, with a variety of nucleophiles proceeded efficiently. These processes represent the first examples of high-yielding nucleophilic substitution reactions of α-alkoxyphosphonium salts. The reactivity of these salts was determined by a balance between steric and electronic factors, respectively, represented by cone angles θ and CO stretching frequencies ν (steric and electronic parameters, respectively). In addition, a novel reaction of α-alkoxyphosphonium salts derived from Ph3P with Grignard reagents was observed to take place in the presence of O2 to afford alcohols in good yields. A radical mechanism is proposed for this process that has gained support from isotope-labeling and radical-inhibition experiments. A dramatic change in the reactivity of an α-alkoxyphosphonium salt toward nucleophiles is observed due to the steric and electronic nature of the phosphine substituents. By changing the type of phosphorus substituents, the reaction pathway can be controlled to proceed selectively by substitution or a new radical reaction (see scheme; OTf=trifluoromethansulfonate, TMS=trimethylsilyl, o-tol=tolyl). Copyright
- Goto, Akihiro,Otake, Kazuki,Kubo, Ozora,Sawama, Yoshinari,Maegawa, Tomohiro,Fujioka, Hiromichi
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p. 11423 - 11432
(2012/11/07)
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- Indium(i)-catalyzed alkyl-allyl coupling between ethers and an allylborane
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An efficient method for alkyl-allyl cross-coupling between ethers and a 9-BBN-derived allylborane catalyzed by indium(i) triflate has been developed. The allylborane proved to be essential to obtain the desired products in high yields. The reaction displayed good substrate scope including high functional group tolerance. The Royal Society of Chemistry 2011.
- Dao, Hai Thanh,Schneider, Uwe,Kobayashi, Shu
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supporting information; experimental part
p. 692 - 694
(2011/03/22)
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- Chemoselective etherification of benzyl alcohols using 2,4,6-trichloro-1,3, 5-triazine and methanol or ethanol catalyzed by dimethyl sulfoxide
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An efficient method for the transformation of benzyl alcohols into their methyl or ethyl ethers has been established using 2,4,6-trichloro-1,3,5-triazine (TCT) and dimethyl sulfoxide in methanol or ethanol. This procedure chemoselectively converts benzylic hydroxys into their methyl or ethyl ethers in the presence of aliphatic or phenolic hydroxys. Georg Thieme Verlag Stuttgart.
- Sun, Lili,Guo, Yuping,Peng, Guisheng,Li, Chunbao
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experimental part
p. 3487 - 3491
(2009/05/26)
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- A novel palladium-catalyzed hydroalkoxylation of alkenes with a migration of double bond
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A novel palladium-catalyzed addition of alcohols to olefins was developed, in which a migration of double bond was involved. By this new method, a variety of allylic ethers were prepared with moderate to high yields under mild conditions. The Royal Society of Chemistry.
- Tan, Jiajing,Zhang, Zuhui,Wang, Zhiyong
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experimental part
p. 1344 - 1348
(2008/10/09)
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- Regio- And stereoselective synthesis of alkyl allylic ethers via gold(l)-catalyzed intermodular hydroalkoxylation of allenes with alcohols
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Reaction of 1-phenyl-1,2-butadiene with 2-phenyl-1-ethanol catalyzed by a 1:1 mixture of a gold(l) W-heterocyclic carbene complex and AgOTf at room temperature for 1 h led to isolation of (E)-(3-phenethoxy-1-butenyl)benzene in 96% yield as a single regio-
- Zhang, Zhibin,Widenhoefer, Ross A.
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supporting information; experimental part
p. 2079 - 2081
(2009/04/10)
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- Applications of lanthanide trichloride hydrates prepared from mischmetall in Luche-type reduction
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An inexpensive alloy of light lanthanides, called Mischmetall, has been used in the preparation of a mixture of lanthanide trichloride hydrates. The use of this new type of material is described in Luche-type reductions. Georg Thieme Verlag Stuttgart.
- Lannou, Marie-Isabelle,Hélion, Florence,Namy, Jean-Louis
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p. 2707 - 2710
(2008/02/12)
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- Transetherification of allylic and benzylic ethers in the presence of ferric ion
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Alcoholysis of allylic, secondary and tertiary benzylic ethers is proceeded efficiently in the presence of catalytic amounts of ferric ion as anhydrous FeCl3 and Fe(ClO4)3.
- Salehi, Peyman,Irandoost, Mohsen,Seddighi, Behnam,Kargar Behbahani, Farahnaz,Tahmasebi, Daryush Poor
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p. 1743 - 1747
(2007/10/03)
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- Molybdenum(II)- and tungsten(II)-catalyzed allylic substitution
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The molybdenum(II) complexes Mo(CO)5(OTf)2 (7a), [Mo(CO)4Br2]2 (8a), their tungsten(II) congeners 7b and 8b, and bimetallic complex Mo(CO)3(MeCN)2(SnCl3)Cl (9a) have been found to catalyze the C-C bond-forming allylic substitution with silyl enol ethers derived from β-dicarbonyls (e.g., 16 + 30 → 46) or from simple ketones (e.g., 16 + 32 → 50), aldehydes, and esters as nucleophiles under mild conditions (room temperature, 1-2 h). Methanol, as a prototype oxygen nucleophile, reacts in a similar fashion (e.g., 16 + MeOH → 43). Mechanistic and stereochemical experiments are indicative of Lewis-acid catalysis rather than a metal template-controlled process.
- Malkov, Andrei V.,Baxendale, Ian R.,Dvorak, Dalimil,Mansfield, Darren J.,Kocovsky, Pavel
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p. 2737 - 2750
(2007/10/03)
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- Selective and efficient alcoholyses of allylic, secondary- and tertiary benzylic alcohols in the presence of iron(III)
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An efficient and selective method for the conversion of allylic, secondary- and tertiary benzylic alcohols into their corresponding ethers in the presence of iron(III) as FeCl3 and Fe(ClO4)3 under solvolytic condition is d
- Salehi, Peyman,Iranpoor, Nasser,Behbahani, Farahnaz Kargar
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p. 943 - 948
(2007/10/03)
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- Synthesis of new chiral catalysts, isoquinuclidinylmethanethiols, for the enantioselective addition of diethylzinc to aryl aldehydes
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New chiral ligands, isoquinuclidinylmethanethiols, were prepared and their catalytic abilities of asymmetric induction were examined in the addition of diethylzinc to aldehydes to furnish secondary alcohols in up to 94% ee.
- Nakano, Hiroto,Iwasa, Kazuto,Hongo, Hiroshi
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p. 267 - 274
(2007/10/03)
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- Catalytic and Efficient Cleavage of Allylic and Tertiary Benzylic Ethers and Esters with Ce(IV)
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The reaction of cerium(IV) as ceric ammonium nitrate (CAN) with a variety of allylic and tertiary benzylic ethers and esters has been examined in different alcohols and acetic acid under catalytic and mild conditions.Experiments have been conducted to elu
- Iranpoor, Nasser,Mottaghinejad, Enayatolah
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p. 7299 - 7306
(2007/10/02)
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- Cerium(IV), as a selective and efficient catalyst for alcoholyses of allylic and tertiary benzylic alcohols
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An efficient and selective method is described for the catalytic conversion of allylic, and tertiary benzylic alcohols into their corresponding ethers in the presence of Ce(IV) under solvolytic and non- solvolytic conditions.
- Iranpoor, Nasser,Mothaghineghad, Enayatholah
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p. 1859 - 1870
(2007/10/02)
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- Photochemistry of Arylbutadienes. Part 2. Preparation and Photochemistry of 1-(Substituted-aryl)butadienes. A Ground-state Substituent Effect on an Excited-state Reaction
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Yields and quantum yields are reported for the photoaddition of methanol to 1-phenylbutadiene and eight substituted 1-phenylbutadienes.For allyl and homoallyl products log Φ correlates more satisfactorily with ground-state substituent constants than with excited-state constants; for cyclopropylmethyl products, no correlation is observed with either set of constants.
- Baldry, Peter J.
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p. 805 - 808
(2007/10/02)
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- Photochemistry of Arylbutadienes. Part 3. Mechanisms of Photoaddition of Methanol to 1-Arylbutadienes
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The mechanism of formation of methyl ethers from irradiation of 1-arylbutadienes in methanol has been studied by deuterium labelling, fluorescence quenching, sensitisation, and kinetic studies.Cyclopropylmethyl ethers arise by a bicyclobutane mechanism; allyl and homoallyl ethers are formed by reaction of methanol with the 1Bu-like excited singlet diene to produce carbocation intermediates.
- Baldry, Peter
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p. 809 - 815
(2007/10/02)
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