- Oxalic Diamides and tert-Butoxide: Two Types of Ligands Enabling Practical Access to Alkyl Aryl Ethers via Cu-Catalyzed Coupling Reaction
-
A robust and practical protocol for preparing alkyl aryl ethers has been developed, which relies on using two types of ligands to promote Cu-catalyzed alkoxylation of (hetero)aryl halides. The reaction scope is very general for a variety of coupling partners, particularly for challenging secondary alcohols and (hetero)aryl chlorides. In case of coupling with aryl chlorides and bromides, two oxalic diamides serve as the powerful ligands. The tert-butoxide is first demonstrated as a ligand for Cu-catalyzed coupling reaction, leading to alkoxylation of aryl iodides complete at room temperature. Additionally, a number of carbohydrate derivatives are applicable for this coupling reaction, affording the corresponding carbohydrate-aryl ethers in 29-98% yields.
- Chen, Zhixiang,Jiang, Yongwen,Zhang, Li,Guo, Yinlong,Ma, Dawei
-
supporting information
p. 3541 - 3549
(2019/02/26)
-
- Concurrent synthesis of vanillin and isovanillin
-
A method for concurrent synthesis of vanillin and isovanillin has been developed by a nonregioselective Vilsmeier-Haack reaction of O-alkyl guaiacols. O-Alkylation of guaiacol provided the corresponding O-alkyl guaiacol (1), which was then formylated with N-methylformanilide/phosphorus oxychloride to give a mixture of 4-alkoxy-3-methoxy-benzaldehyde (2) and 3-alkoxy-4- methoxybenzaldehyde (3). Finally, the obtained mixture underwent a selective dealkylation by anhydrous aluminium trichloride, while leaving methyl groups intact to simultaneously achieve the significant fine chemicals vanillin and isovanillin.
- Huang, Wei-Bin,Du, Cai-Yan,Jiang, Jian-An,Ji, Ya-Fei
-
p. 2849 - 2856
(2013/07/26)
-
- A single phosphine ligand allows palladium-catalyzed intermolecular C-O bond formation with secondary and primary alcohols
-
Forging a bond: An efficient, general palladium catalyst for C-O bond-forming reactions of secondary and primary alcohols with a range of aryl halides has been developed using the ligand 1. Heteroaryl halides, and for the first time, electron-rich aryl halides can be coupled with secondary alcohols. A diverse set of substrate combinations are possible with just a single ligand, thus obviating the need to survey multiple ligands. Copyright
- Wu, Xiaoxing,Fors, Brett P.,Buchwald, Stephen L.
-
supporting information; experimental part
p. 9943 - 9947
(2011/12/05)
-
- Microwave-assisted demethylation of methyl aryl ethers using an ionic liquid
-
An efficient demethylation of methyl aryl ethers using an ionic liquid, 1-n-butyl-3-methylimidazolium bromide ([bmim][Br]) has been developed. Methyl aryl ethers are successfully cleaved by the halide anion of [bmim][Br], without aid of any other activating agents. In this reaction, microwave irradiation was found to be crucial for the effective conversion. The newly developed protocol is a very attractive green chemical process as it utilizes minimal amount of cleaving reagents and does not require additional activating agents or solvents. Under the conditions described herein, a broad range of methyl aryl ethers were converted to the corresponding phenolic compounds in moderate to excellent yields in a short time. Georg Thieme Verlag Stuttgart New York.
- Park, Jiyeon,Chae, Junghyun
-
experimental part
p. 1651 - 1656
(2010/08/22)
-
- Copper-catalyzed etherification of aryl iodides using KF/Al 2O3: An improved protocol
-
A simple and efficient method for the coupling of aryl iodides with aliphatic alcohols and phenols that does not require the use of alkoxide bases is described. This C-O bond forming procedure shows that the combination of air stable CuI and 1,10-phenanthroline in the presence of KF/Al2O 3 comprises an extremely efficient and general catalyst system for the etherification of aryl iodides. Different functionalized aryl iodides were coupled with alcohols and phenols using this method.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Mohadjerani, Maryam,Alikarami, Mohammad
-
p. 1101 - 1104
(2007/10/03)
-
- Use of tunable ligands allows for intermolecular Pd-catalyzed C-O bond formation
-
Bulky biaryl phosphine ligands facilitate Pd-catalyzed C-O coupling reactions of aryl halides with primary and secondary alcohols by promoting reductive elimination at the expense of β-hydride elimination. The key to their success is the ability to match the size of the ligand to that of the combination of substrates. The efficient coupling of a number of unactivated aryl chlorides and bromides with cyclic and acyclic secondary alcohols was achieved. This included the coupling of allylic alcohols for the first time in a Pd-catalyzed coupling process.
- Vorogushin, Andrei V.,Huang, Xiaohua,Buchwald, Stephen L.
-
p. 8146 - 8149
(2007/10/03)
-
- An efficient lutidine-assisted etherification of phenols with alkyl chloride in water
-
An efficient etherification of phenol derivatives with alkyl chloride in water was achieved. The reactivity of the ether bond forming reaction was activated by addition of 2,6-lutidine.
- Aki, Shinji,Nishi, Takao,Minamikawa, Jun-Ichi
-
p. 940 - 941
(2007/10/03)
-
- Copper-catalyzed coupling of aryl iodides with aliphatic alcohols.
-
[reaction: see text] A simple and mild method for the coupling of aryl iodides and aliphatic alcohols that does not require the use of alkoxide bases is described. The reactions can be performed in neat alcohol. For more precious alcohols, the etherificat
- Wolter, Martina,Nordmann, Gero,Job, Gabriel E,Buchwald, Stephen L
-
p. 973 - 976
(2007/10/03)
-
- The creation of long-lasting glassy columnar discotic liquid crystals using 'dimeric' discogens
-
'Dimeric' discogens have been synthesised which have two triphenylene nuclei, each of which bears five β-OC6H13 substituents, which are linked through the remaining β positions by a flexible O(CH2)(n)O polymethylene chain
- Boden, Neville,Bushby, Richard J.,Cammidge, Andrew N.,El-Mansoury, Ahmed,Martin, Philip S.,Lu, Zhibao
-
p. 1391 - 1402
(2007/10/03)
-
- Template Effects. 4. Ion Pairing of Aryloxide Ions with Alkali Cations in 99percent Me2SO: Influence on the Rate of Formation of Benzo-18-crown-6 and of Other Williamson-Type Reactions
-
The effect of alkali metal ions on the rate of formation of benzo-18-crown-6 in 99percent Me2SO by cyclization of the conjugate base of o-hydroxyphenyl 3,6,9,12-tetraoxa-14-bromotetradecyl ether has been quantitatively accounted for according to a scheme involving separate contributions from free (ki) and cation-paired (kip) phenoxide ion.The study has included several additional intra- and intermolecular alkylations of phenoxide ions as reference reactions to provide a set of 25 equilibrium constants for the association of five different phenoxides with the five alkali cations.Both Coulombic interaction and coordination with the neutral oxygen donors are important in determining ion pair stability, but the order in all cases is dominated by Coulombic interaction.This suggests contact interaction in the phenoxide-cation pairs, which is also consistent with evidence from the UV spectra.Whereas the rate of formation of B18C6 is depressed by Li+ (kip/ki + (kip/ki = 100).In contrast, in the reference reactions the ion pairs with the alkali are either negligibly reactive or much less reactive than the free anions.The association constants of the alkali cations with B18C6 have been determined under the same conditions.A comparative analysis of the extent of interaction of the cations with the reactant, transition state, and reaction product of the crown ether forming reaction shows that the transition state binds cations more strongly than the reactant or reaction product and reveals that cation interaction with both the negative charge and the neutral donors bear significant contribution to the stability of the ion pair transition state.A rationale for the template effect is presented in terms of proximity effects and chemical effects arising from interaction of the cation with the nucleophilic site of the reactant.
- Illuminati, Gabriello,Mandolini, Luigi,Masci, Bernardo
-
p. 555 - 563
(2007/10/02)
-