- 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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- Exploring the reaction pathways of Pd(II)-catalyzed cyclohexene oxidation with molecular oxygen: Vinylic and allylic oxidation, disproportionation and oxidative dehydrogenation
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Palladium(ii) salts are able catalysts to promote different oxidative transformations of cyclohexene in the presence of molecular oxygen: vinylic and allylic oxidation and disproportionation. In this paper, we assessed the main aspects that govern these reactions, by using palladium salts (i.e. PdCl2, Pd(OAc)2, Pd(acac)2 and Pd(CF3COO)2) in protic solvents (i.e. CH3COOH and CH3OH). When carried out in CH3COOH solutions at 333 K, the Pd(ii)-catalyzed oxidation reactions preferentially convert cyclohexene to 2-cyclohexenil-1-acetate. Benzene was the secondary product. It was found that the efficiency of the palladium reoxidant followed the trend: Fe(NO3)3 > LiNO3 > CuCl2 > FeCl3. Pd(OAc)2 was the most active catalyst. Replacing Cu(OAc)2 by Fe(NO3)3 notably enhances the conversion of cyclohexene and the selectivity of 2-cyclohexenyl-1-acetate, reducing significantly the reaction time from 22 to 3 h. Conversely, when performed in CH3OH solutions, the reaction had its selectivity drastically changed; benzene and cyclohexane were the most selectively formed products (i.e. through disproportionation reaction). In this case, the reaction occurred at room temperature and in the absence of a reoxidant. Hence, Pd(CF3OO)2 is the most active and selective catalyst. The addition of the Fe(NO3)3 reoxidant and increasing the reaction temperature to 328 K resulted in the formation of 1,2-dimethoxycyclohexane and benzene as major products (i.e. allylic oxidation and oxidative dehydrogenation products, respectively). Catalytic cycles for these transformations were proposed based on experimental data and palladium chemistry.
- Da Silva,Berlini
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p. 7996 - 8005
(2016/09/12)
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- InI3/me3sii-catalyzed direct alkylation of enol acetates using alkyl acetates or alkyl ethers
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A combined Lewis acid of InI3 and Me3SiI was used to catalyze the direct coupling reactions of enol acetates with alkyl acetates or alkyl ethers without generating metal waste. The easily-handled alkylating reagents enlarged the application area of this coupling reaction. 2011 The Chemical Society of Japan.
- Onishi, Yoshiharu,Nishimoto, Yoshihiro,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 1223 - 1225
(2011/11/29)
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- New oxidative transformations of alkenes and alkynes under the action of diacetoxyiodobenzene
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Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.
- Yusubov,Zholobova,Filimonova,Chi, Ki-Whan
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p. 1735 - 1742
(2007/10/03)
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- Six- and five-membered 3-alkoxy-2-lithiocycloalkenes: New stable non-anionic β-functionalised organolithium compounds
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Naphthalene-catalysed reductive lithiation of various functionalised chlorocycloalkenes 18 leads to the corresponding non-anionic β-alkoxyfunctionalised organolithium reagents 14. Their reaction with different electrophiles, such as water, aldehydes, keto
- Yus, Miguel,Ramón, Diego J,Gómez, Inmaculada
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p. 5163 - 5172
(2007/10/03)
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- Synthesis of allylic esters and ethers using polymer-supported selenium bromidet
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The treatment of adducts from polymer-supported selenium bromide on olefins with anhydrous carboxylate or alcohol and oxidation of the resulting products afford allylic esters and ethers in good yield and purity.
- Sheng, Shou-Ri,Huang, Xian
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p. 184 - 185
(2007/10/03)
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- The reaction of cyclic allylic alcohols with aliphatic alcohols in the presence of cerium(III) chloride
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Cyclic secondary and tertiary allylic alcohols react with primary aliphatic alcohols in the presence of cerium(III) chloride heptahydrate to give alkyl allylic ethers. When secondary or tertiary aliphatic alcohols are used 1,3-dienes are obtained from allylic alcohols heaving the 3-methyl-2-en-1-ol moiety (3-8, 13-15).
- Uzarewicz,Dresler
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p. 181 - 195
(2007/10/03)
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- Stereodirecting Effect of a Substrate Methoxy Substituent on the Addition of Singlet Methylene to a Double Bond
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The stereodirecting effects of substrate methoxy, hydroxy, methylthio, and methyl substituents were examined in the addition of 1:CH2 to the double bonds of substrates 1a-d.The carbene, generated by photolysis of CH2N2, inserted into the C-H bonds of solvent and substrate, added to the substrate double bond to give products 2a-d, and attacked the oxygen or sulfur atom of substrates 1a-c to produce ylide intermediates which underwent 2,3-sigmatropic rearrangement to give products 3a-c.A preference for addition syn to the methoxy group of substrate 1a was observed when the reaction was run in pentane solution (syn-2a/anti-2a, 1.14 +/- 0.02), while a preference for formation of anti-2a was observed in diethyl ether solution (syn-2a/anti-2a, 0.92 +/- 0.03).A preference for 1:CH2 addition anti to the substrate substituent was observed for substrates 1b-d in both pentane and ether solution.The effect of the methoxy substituent was also examined in the addition of 1:CH2 to syn-7-methoxynorbornene (5b).Explanations for the substituent effects are offered based on both steric hindrance and interaction between 1:CH2 and the substituent, including formation and subsequent reaction of the ylide intermediates.
- Young, Terry A.,O'Rourke, Colleen,Gray, Nathan B.,Lewis, Brian D.,Dvorak, Curt A.,et al.
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p. 6224 - 6228
(2007/10/02)
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- Model Systems for Cytochrome P450 Dependant Mono-oxygenases. Part 7. Alkene Epoxidation by Iodosylbenzene Catalyzed by Ionic Iron(III) Tetrarylporphyrins Supported on Ion-exchange Resins
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Ionic iron(III) tetraarylporphyrins are readily adsorbed onto cross-linked polystyrene ion-exchange resins.These supported metalloporphyrins can act as heterogenous catalysts for the oxidation of organic compounds by iodosylbenzene in methanolic solution.Their catalytic activity for the epoxidation and allylic oxidation of cyclohexene and the epoxidation of (Z)-cyclooctene has been studied.With cyclohexene, epoxidation is favoured by increased cross-linking of the resin support, and allylic oxidation is shown to arise largely from an autoxidation which can be minimised by carrying out the reaction under nitrogen. (Z)-cyclooctene gives only epoxidation which is also favoured by increased cross-linking and is unaffected by changes in the surface area of the support.The influence of the support cross-linking on catalyst performance is discussed.Supproted anionic iron(III) porphyrins are poor catalysts unless they are sterically hindered with ortho-groups on the aromatic substituents.The fate of the oxidant in the heterogeneous oxidations is examined and comparison with the analogous homogeneous reactions suggests that some of the oxidant is consumed in oxidising the polymer support.A brief study of the oxidation of cyclohexene by iodosylbenzene catalyzed by a cation exchange resin in its acidic form, in the absence of metalloprophyrin, is reported.
- Leanord, Donald R.,Smith, John R. Lindsay
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p. 1917 - 1923
(2007/10/02)
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- Deamination Reactions, 51. - Decomposition of Bicyclohexane-exo-6-diazonium Ions
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The nitrous acid deamination of the amine 13, the copper(II)-induced cleavage of the nitrosourea 19, and the thermolysis of the nitrosoamide 20 were used to generate the diazonium ion 7.In contrast to previous work, performed in the presence of base, the neutral to weakly acidic conditions of the present study afforded substantial fractions (30-40percent) of bicyclohex-exo-6-yl products (15).Small quantities of bicyclohex-endo-6-yl (14), bicyclohex-2-yl (25, 26) and 3-cyclohexen-1-yl (27) derivatives were also detected, the latter arising by a 1,3-hydride shift.These results, unprecedented with higher homologs of 7, suggest a largely "classical" bicyclohex-6-yl cation (21) as the initially formed intermediate.Capture of 21 is thought to compete with disrotatory transformation to the cyclohexenyl cation 12. - Keywords: Bicyclohex-6-yl derivatives/ Diazonium ions/ Electrocyclic reactions/ Nucleophilic displacement
- Kirmse, Wolfgang,Hellwig, Georg
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p. 389 - 392
(2007/10/02)
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- Nitrosonium Ion Promoted Iodination and 1,2-Iodofunctionalization of Cyclohexene
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The promoting influence of NO+BF4- on the addition of I2 or 'I+Nu-' couples to cyclohexene (1) in the presence of O2 is described. 1-Acetoxy-2-iodocyclohexane is obtained in 89percent isolated yield from the reaction of I2, 1 and CH3COOH in CH2Cl2, and the corresponding methoxy- and acetamido-substituted iodocyclohexanes are obtained in 96 and 92percent yield, when methanol and acetonitrile, respectively, are added.Applications of the method to the synthesis of cis-1,2-cyclohexanediol (Woodward reaction) and bis(2-iodocyclohexyl) ether is described.
- Radner, Finn
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p. 902 - 907
(2007/10/02)
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- Photochemistry of Cyclohepta-1,3-diene and Cyclohepta-1,3,5-triene. Photochemical Formation and Chemical Reactivity of the Strained trans-Isomer
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The direct and sensitized photolyses of cis,cis-cyclohepta-1,3-diene and cis,cis,cis-cyclohepta-1,3,5-triene have been studied in detail in search of the trans-isomer.Low-temperature irradiations and trapping experiments with acidic methanol have revealed that the primary process for the excited singlet and triplet states of cycloheptadiene is not direct disrotatory cyclization but geometrical isomerization to the highly strained cis,trans-isomer, which is detected spectroscopically, while no intermediacy of any transient species can be detected spectroscopically or trapped chemically in the photolyses of cycloheptatriene.The cis,trans-cycloheptadiene generated photochemically cyclizes thermally to bicyclohept-6-ene in neutral media or gives adducts, 3-methoxycycloheptene and 2-methoxynorcarane, in acidic methanol.The kinetic and thermodynamic parameters for the photochemical and the subsequent thermal processes are discussed.
- Daino, Yoshihiko,Hagiwara, Shoji,Hakushi, Tadao,Inoue, Yoshihisa,Tai, Akira
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p. 275 - 282
(2007/10/02)
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- Pyridylseleno Group in Organic Synthesis. Part 4. Oxyseleniation of Olefins using Pyridine-2-selenenyl Bromide as a Selenium Reagent and its Utilization in the Synthesis of 2-Pyridyl Vinylic Selenides
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The reaction of olefins with pyridine-2-selenenyl bromide in methanol as solvent affords β-methoxyalkyl 2-pyridyl selenides (A) in good to excellent yields.This reaction also proceeds in acetic acid and aqueous tetrahydrofuran to give acetoxyseleniated an
- Toshimitsu, Akio,Owada, Hiroto,Terao, Keiji,Uemura, Sakae,Okano, Masaya
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p. 373 - 378
(2007/10/02)
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- SYN-STEREOSELECTIVE EPOXIDATION OF ALLYLIC ETHERS USING CF3CO3H
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Good syn-stereoselectivity is observed in the epoxidation of allylic ethers with CF3CO3H, indicating a new type of hydrogen-bonded transition state.
- McKittrick, Brian A.,Ganem, Bruce
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p. 4895 - 4898
(2007/10/02)
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- ETHER FORMATION FROM ALLYLIC ALCOHOLS CATALYZED BY SAMARIUM TRICHLORIDE
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The behaviour of various allylic alcohols in the presence of catalytic amounts of SmCl3 (by heating in 1,2-dichloroethane) has been studied.Diallyl ethers are obtained in many cases in good yields.Mixed allyl alkyl ethers are also prepared if 2-5 equivalents of an aliphatic alcohol is present.The reactions are interpreted as proceeding through a pseudo allylic carbonium intermediate initiated by a preliminary complexation of the allyl hydroxyl to the samarium ion.
- Ouertani, Mohsen,Collin, Jacqueline,Kagan, Henri B.
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p. 3689 - 3693
(2007/10/02)
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- COHALOGENATION DES OLEFINES : APPLICATION A LA SYNTHESE D'ALCOOLS ALLYLIQUES
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Alkenes 1 a-f are converted in three steps into the ally alcohols 4 a-f ; the cohalogenation of alkenes by NBS in alcohols constitutes the first step of this synthesis.
- Rodriguez, J.,Dulcere, J-P,Bertrand, M.
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p. 527 - 528
(2007/10/02)
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- ETUDE DE L'HYDROGENATION DE L'α-TERPINENE ET DU DIHYDRO-2,3 ANISOLE CATALYSEE PAR LE PHENANTHRENE CHROME TRICARBONYLE
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The hydrogenation of α-terpinene and 2,3-dihydroanisole catalysed by phenanthrenechromium tricarbonyl in cyclohexane is described.The catalytic reaction is accelerated when small amount of ketone are added to the solution.Attempts to induce asymmetric syn
- Maux, P.Le,Dabard, R.,Simonneaux, G.
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- New Aspects of the Telluroxide Elimination. A Facile Elimination of sec-Alkyl Phenyl Telluroxide Leading to Olefins, Allylic Alcohols, and Allylic Ethers
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The utility of the telluroxide for olefin synthesis, a reaction which previously appeared to be of little value, is described.Treatment of sec-alkylphenyltellurium dibromides, except for the cyclohexyl system, with aqueous NaOH at room temperature affords olefins, allylic alcohols, and/or allylic ethers in high yields presumably via the formation of sec-alkyl phenyl telluroxides and their facile telluroxide elimination.As to the formation of linear olefins, more preference for elimination toward the less substituted carbon was observed than the selenoxide and sulfoxide eliminations.In the cyclododecyl case only trans-cyclododecene was formed as an olefin component in a sharp contrast to the selenoxide elimination that affords a 1:1 mixture of cis and trans isomers.On the contrary, in the n-alkyl and cyclohexyl cases the corresponding telluroxides are stable compounds that afford similar elimination products including vinylic ethers only by neat pyrolysis at temperatures above 200 deg C.
- Uemura, Sakae,Fukuzawa, Shin-ichi
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p. 2748 - 2752
(2007/10/02)
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- A FACILE METHOD FOR OXYTELLURATION OF OLEFINS
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Treatment of olefins with phenyltellurium(II) or (IV) species in alcohol at room to reflux temperature for 1-24 h produces the corresponding (2-alkoxyalkyl)phenyltellurium dihalides in good yields, the reaction being trans-stereoselective and highly regioselective.
- Uemura, Sakae,Fukuzawa, Shin-ichi,Toshimitsu, Akio,Okano, Masaya
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p. 1177 - 1180
(2007/10/02)
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- CATALYTIC HYDROGENATION OF α-TERPINENE AND 2,3-DIHYDROANISOLE BY A PHENANTHERENECHROMIUM TRICARBONYL COMPLEX
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The hydrogenation of α-terpinene and 2,3-dihydroanisole catalysed by phenanthrenechromium tricarbonyl is described and discussed.
- Maux, Paul Le,Simonneaux, Gerard
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p. C24 - C26
(2007/10/02)
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