21144-16-1Relevant academic research and scientific papers
Cross-Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N-Coordinated Nickel Complex
Hashimoto, Toru,Shiota, Keisuke,Funatsu, Kei,Yamaguchi, Yoshitaka
supporting information, p. 1625 - 1630 (2021/01/26)
A synthesis of alkyl aryl ethers was achieved via the cross-coupling of aryl halides with primary and secondary aliphatic alcohols catalyzed by a bench-stable nickel complex supported by a monoanionic O,N,N-tridentate ligand. This nickel-catalyzed reaction proceeds smoothly in the absence of a phosphine ligand, affording alkyl aryl ethers in moderate to good yields. (Figure presented.).
Synthesis of aryl ethers from benzoates through carboxylate-directed C-H-activating alkoxylation with concomitant protodecarboxylation
Bhadra, Sukalyan,Dzik, Wojciech I.,Goo?en, Lukas J.
, p. 2959 - 2962 (2013/04/10)
One in, one out: In the presence of a copper/silver bimetallic catalyst system, aromatic carboxylate salts undergo ortho C-H alkoxylation with concomitant loss of the carboxylate directing group in a protodecarboxylation step (see scheme, FG=functional group). This process provides a convenient synthetic access to the important class of aromatic ethers from widely available carboxylic acids. Copyright
Synthesis of aryl ethers from aromatic carboxylic acids
Bhadra, Sukalyan,Dzik, Wojciech I.,Goossen, Lukas J.
supporting information, p. 2387 - 2390 (2013/09/23)
A silver/copper bimetallic catalyst system promotes the decarboxylative Chan-Evans-Lam alkoxylation of ortho-substituted aromatic carboxylate salts with tetraalkyl orthosilicates or triaryl borates. Non-ortho-substituted carboxylates are alkoxylated via an ortho-C-H-alkoxylation with concomitant cleavage of the carboxylate directing group via protodecarboxylation. This way, meta-substituted carboxylates are converted into para-substituted alkoxyarenes and vice versa. The combined processes provide a convenient synthetic entry to the important class of aromatic ethers from widely available carboxylic acids.
Benzyl protection of phenols under neutral conditions: Palladium-catalyzed benzylations of phenols
Kuwano, Ryoichi,Kusano, Hiroki
supporting information; experimental part, p. 1979 - 1982 (2009/04/10)
Benzyl protection of phenols under neutral conditions was achieved by using a Pd(n3-C3H5)Cp-DPEphos catalyst. The palladium catalyst efficiently converted aryl benzyl carbonates into benzyl-protected phenols through the decarboxylative etherification. Alternatively, the nucleophilic substitution of benzyl methyl carbonates with phenols proceeded In the presence of the catalyst, yielding aryl benzyl ethers.
An improved Cu-based catalyst system for the reactions of alcohols with aryl halides
Altman, Ryan A.,Shafir, Alexandr,Choi, Alice,Lichtor, Phillip A.,Buchwald, Stephen L.
, p. 284 - 286 (2008/09/17)
(Chemical Equation Presented) The use of 3,4,7,8-tetramethyl-1,10- phenanthroline (Me4Phen) as a ligand improves the Cu-catalyzed cross-coupling reactions of aryl iodides and bromides with primary and secondary aliphatic, benzylic, allylic, and propargylic alcohols. Most importantly, by employing this catalyst system, the need to use an excessive quantity of the alcohol coupling partner is alleviated. The relatively mild conditions, short reaction times, and moderately low catalyst loading allow for a wide array of functional groups to be tolerated on both the electrophilic and nucleophilic coupling partners.
Practical synthesis of aromatic ethers by SNAr of fluorobenzenes with alkoxides
Rodriguez, Juan R.,Agejas, Javier,Bueno, Ana B.
, p. 5661 - 5663 (2007/10/03)
Aromatic fluorines have been substituted by alkoxides in a variety of activated and unactivated aromatic systems.
Bu3SnH mediated oxidative radical cyclisations: Synthesis of 6H-benzo[c]chromen-6-ones
Bowman, Russell,Mann, Emma,Parr, Jonathan
, p. 2991 - 2999 (2007/10/03)
Attempts to synthesise 6H-benzo[c]chromen-6-ones by Bu3SnH mediated cyclisation of o-(benzoyl)aryl radicals failed because of the preferred trans conformation of the ester. This problem was overcome by using cyclisation of o-(benzyloxy)aryl and o-[(aryloxy)methyl]aryl radicals to yield 6H-benzo[c]chromenes followed by oxidation to the 6H-benzo[c]chromen-6-ones. 3-Methoxy-6H-benzo[c]chromen-6-one 1, one of the main biologically active constituents of shilajit, a herbal medicine used in countries surrounding the Himalayan mountains, was synthesised using Bu3SnH mediated cyclisation of 1-benzyloxy-2,4-dibromo-5-methoxybenzene 31 to yield 3-methoxy-6H-benzo[c]chromene 25 followed by PCC oxidation of the 6-position. In order to avoid the problems of rearrangement, the aryl radical cyclisation must be designed such that whichever way the spirodienyl intermediate rearranges, the same product is obtained. For instance, the Bu3SnH mediated cyclisation of 1-iodo- and 1-bromo-2-(3-methoxy-phenyloxymethyl)benzenes 22 and 23 respectively gave both the isomers, 1-methoxy-6H-benzo[c]chromenes 24 and 3-methoxy-6H-benzo[c]chromenes 25 via rearrangement of the intermediate spirodienyl radical. The synthesised 6H-benzo[c]chromenes were oxidised in high yield to the corresponding 6H-benzo[c]chromen-6-ones. The mechanism of the 'oxidative' Bu3SnH mediated cyclisation is discussed.
SELECTIVE DEALKYLATIONS OF ARYL ALKYL ETHERS AND THIOETHERS BY SODIUM IN HMPA
Testaferri, L.,Tiecco, M.,Tingoli, M.,Chianelli, D.,Montanucci, M.
, p. 3687 - 3692 (2007/10/02)
The reaction of sodium with bis- and tris(alkoxy)benzenes in HMPA gives selectively the products of monodealkylation.The reaction proceeds through a dianion which fragments into an alkyl and an aryloxy anion.The positional selectivity of this fragmentation is governed by the structure of both the alkyl and aryloxy groups.With bis- and tris(alkoxy)benzenes which for symmetry reasons can afford aryloxy anions having the same basicity, the dealkylation involves exlusively the less substituted alkyl group.On the contrary, in the asymmetric terms, the positional selectivity of the dealkylation process is governed by the basicity of the aryloxy anion.On the basis of these concepts several efficient and synthetically useful reactions have been developed.In most cases the selectivity obtained in the present reactions in different from that observed with other previously developed methods which use sodium methoxide or sodium alkenethiolates in HMPA.It is shown that the appropriate choice of the reagent allows selective dealkylation of the desired alkoxy group of a poly(alkoxy)benzene.The reaction of sodium with bis(alkylthio)benzenes in HMPA gives the bis(mercapto)benzenes.If the reduction is carried out with a solution of sodium in HMPA, the reaction gives instead the products of monodealkylation.This however is not selective.It is suggested that in the case of thioethers the dealkylation products originate from the fragmentation of the radical anions.
