51241-41-9Relevant academic research and scientific papers
Practical Ligand-Free Copper-Catalysed Short-Chain Alkoxylation of Unactivated Aryl Bromides
Guo, Ying,Fan, Xue-Min,Nie, Min,Liu, Hong-Wei,Liao, Dao-Hua,Pan, Xian-Dao,Ji, Ya-Fei
, p. 4744 - 4755 (2015/08/03)
An efficient and practical short-chain alkoxylation of unactivated aryl bromides has been developed with special attention focussed on the applicability of the reaction. Sodium alkoxide is used as the nucleophile, and the corresponding alcohol as the solvent. The reaction requires neither precious metals nor organic ligands. It uses a catalytic system consisting of copper(I) bromide as a catalyst, the corresponding alkyl formate as a noncontaminating cocatalyst, and lithium chloride as an additive. A wide range of substrates and test cases highlight the synthetic utility of the approach. Considering the commercial accessibility and affordability of the feedstocks, this protocol shows promise as a new alternative for the sustainable preparation of aryl alkyl ethers.
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.
Combined directed remote metalation-transition metal catalyzed cross coupling strategies: The total synthesis of the aglycones of the gilvocarcins V, M, and E and arnottin I
James, Clint A.,Snieckus, Victor
supporting information; experimental part, p. 4080 - 4093 (2009/09/30)
(Chemical Equation Presented) A key directed remote metalation (DreM)-carbamoyl migration strategy was applied in an efficient synthesis of the naturally occurring 6H-naphtho[1,2-b]benzopyran-6-one defucogilvocarcin V (1a, Scheme 11). The required biarylcarbamate 33d was best prepared by a high yielding Suzuki coupling reaction of 31a with the differentially protected trioxygenated naphthalene coupling partner 32d which was synthesized using a selective acylation of a juglone derivative. In the late stages of the synthesis, the triflate 39 served as the common intermediate to install the required C-8 vinyl group of 1a (Stille coupling) as well as the required substituents for the preparation of defucogilvocarcins M (1b) and E (1c). A variety of protecting group strategies were investigated and provided insight into which groups are preferred for the DreM-carbamoyl migration process. The strategic lessons learned from this total synthesis were applied in the successful total synthesis of the structurally similar natural product arnottin I (2).
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.
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.
Photodehalogenation of the Monochloro- and Monofluoroanisoles
Siegman, John R.,Houser, John J.
, p. 2773 - 2779 (2007/10/02)
Evidence is presented for a plurality of mechanisms in the photoreduction and photonucleophilic substitution of the monochloroanisoles in alcohol solvents. 4-Chloroanisole appears to react partly via a radical anion and partly by radicals, while the reactions of 3-chloroanisole are more consistent with aryl cations and aryl radicals.The intermediates in the reaction of 2-chloroanisole, which gives no photosubstitution, are as yet not identified but are probably not radical anions.In the case of 4-chloroanisole, substitution and reduction may proceed from different states.Preliminary results on the fluoroanisoles show the 2-F isomer giving both reduction and substitution and the 3- and 4-F isomers only substitution.
