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1.
Rehanguli Ruzi Junyang Ma Prof. Dr. Xiang-Ai Yuan Wenliang Wang Shanshan Wang Dr. Muliang Zhang Dr. Jie Dai Prof. Dr. Jin Xie Prof. Dr. Chengjian Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(55):12724-12729
An unprecedented deoxygenative arylation of aromatic carboxylic acids has been achieved, allowing the construction of an enhanced library of unsymmetrical diaryl ketones. The synergistic photoredox catalysis and phosphoranyl radical chemistry allows for precise cleavage of a stronger C−O bond and formation of a weaker C−C bond by 1,5-aryl migration under mild reaction conditions. This new protocol is independent of substrate redox-potential, electronic, and substituent effects. It affords a general and promising access to 60 examples of synthetically versatile o-amino and o-hydroxy diaryl ketones under redox-neutral conditions. Furthermore, it also brings one concise route to the total synthesis of quinolone alkaloid, (±)-yaequinolone A2, and a viridicatin derivative in satisfying yields. 相似文献
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Xanath Ispizua-Rodriguez Dr. Socrates B. Munoz Dr. Vinayak Krishnamurti Dr. Thomas Mathew Prof. Dr. G. K. S. Prakash 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(64):15908-15913
A simple and straightforward approach to the synthesis of trifluoromethyl and difluoromethyl ketones from widely available carboxylic acids is disclosed. The transformation utilizes an acyloxyphosphonium ion as the active electrophile, conveniently generated in situ from the carboxylic acid substrate by using commodity chemicals. The utility of the reaction system is exemplified by its chemoselectivity, with tolerance to a variety of important functional groups. The late-stage functionalization of carboxylic acid active pharmaceutical ingredients and pharmaceutically relevant compounds is also discussed. 相似文献
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Ligand‐Free Palladium‐Catalyzed Aerobic Oxidative Coupling of Carboxylic Anhydrides with Arylboronic Acids
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We report a new, effective and environmentally friendly protocol for selective aerobic oxidative coupling of arylboronic acids with carboxylic anhydrides in the presence of ligand‐free palladium catalyst. The aryl benzoates are obtained in good to excellent yields. 相似文献
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Dr. Andreas P. Hring Dennis Pollok Benjamin R. Strücker Vincent Kilian Johannes Schneider Prof.Dr. Siegfried R. Waldvogel 《ChemistryOpen》2022,11(5)
Herein we report a conceptually new non‐decarboxylative electrolysis of carboxylic acids to obtain their corresponding anhydrides as highly valuable reagents in organic synthesis. All carbon atoms of the starting material are preserved in the product in an overall redox‐neutral reaction. In a broad substrate scope of carboxylic acids the anhydrides are generated with high selectivity, which demonstrates the versatility of the developed method. Beneficially, no dehydrating reagents are required in comparison to conventional methods and the synthesis is based on uncritical starting materials using graphite and stainless steel as very inexpensive and eco‐friendly electrode materials. 相似文献
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Conversion of aryl ketones to the corresponding aromatic carboxylic acids has been achieved using sequential treatment of HDNIB and urea–hydrogen peroxide in [bmim]BF4 ionic liquid. 相似文献
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Oliver R. Gedde Andreas Bonde Peter I. Golbækdal Prof. Dr. Troels Skrydstrup 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(34):e202200997
An expedient ex-situ generation of difluoroiodomethane (DFIM) and its immediate use in a Pd-catalyzed difluoromethylation of aryl boronic acids and ester derivatives in a two-chamber reactor is reported. Heating a solution of bromodifluoroacetic acid with sodium iodide in sulfolane proved to be effective for the generation of near stoichiometric amounts of DFIM for the ensuing catalytic coupling step. A two-step difluoromethylation of aryl (pseudo)halides with tetrahydroxydiboron as a low-cost reducing agent, both promoted by Pd catalysis, proved effective to install this fluorine-containing C1 group onto several pharmaceutically relevant molecules. Finally, the method proved adaptable to deuterium incorporation by simply adding D2O to the DFIM-generating chamber. 相似文献
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Lukas J. Goossen Prof. Dr. Christophe Linder Nuria Rodríguez Dr. Paul P. Lange 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(37):9336-9349
A bimetallic catalyst system has been developed that for the first time allows the decarboxylative cross‐coupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non‐coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic cross‐coupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho‐substituted or otherwise activated derivatives to a broad range of ortho‐, meta‐, and para‐substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of CuI/1,10‐phenanthroline (10–15 mol %) and PdI2/phosphine (2–3 mol %) in NMP for 1–24 h, the other involving CuI/1,10‐phenanthroline (6–15 mol %) and PdBr2/Tol‐BINAP (2 mol %) in NMP using microwave heating for 5–10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non‐activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylative cross‐couplings are discussed. 相似文献
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Palladium‐Catalyzed Synthesis of (Hetero)Aryl Alkyl Sulfones from (Hetero)Aryl Boronic Acids,Unactivated Alkyl Halides,and Potassium Metabisulfite
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Andre Shavnya Dr. Kevin D. Hesp Dr. Vincent Mascitti Dr. Aaron C. Smith 《Angewandte Chemie (International ed. in English)》2015,54(46):13571-13575
A palladium‐catalyzed one‐step synthesis of (hetero)aryl alkyl sulfones from (hetero)arylboronic acids, potassium metabisulfite, and unactivated or activated alkylhalides is described. This transformation is of broad scope, occurs under mild conditions, and employs readily available reactants. A stoichiometric experiment has led to the isolation of a catalytically active dimeric palladium sulfinate complex, which was characterized by X‐ray diffraction analysis. 相似文献
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Dr. Tiefeng Xu Qi Wang Zeyi Yang Dr. Lili Yi Jian-Shu Wang Prof. Dr. Wangyang Lu Dr. Jun Ying Prof. Dr. Xiao-Feng Wu 《化学:亚洲杂志》2021,16(15):2027-2030
A palladium supported on graphitic carbon nitride (Pd/g-C3N4) catalyzed carbonylative reaction of aryl bromides and arylboronic acids by has been developed for the construction of diaryl ketones. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction proceeded well to give various diaryl ketones in moderate to good yields. 相似文献
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Activity of 20wt% MO2/Al2O3 catalysts, where M = Mn, Ce and Zr has been studied in ketonisation of the mixtures of propanoic/pentanoic, ethanoic/10-undecenoic and hexanoic/(Z)-9-octadecenoic (oleic) acids. Irrespective of the molecular weights and molar ratios of reacting acids, high yields of ketones were obtained over Mn and Ce oxide catalysts at approximately 673 K. Isomerization of C=C double bonds and partial pyrolysis occurred during catalytic ketonization of 10-undecenoic and oleic acids, diminishing slightly the yield of ketones. The preparation of (Z)-14-tricosen-6-one has been performed, being the starting material for the synthesis of (Z)-9-tricosene - sex attractant of male house fly. 相似文献
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Highly Chemoselective and Versatile Method for Direct Conversion of Carboxylic Acids to Ketones Utilizing Zinc Ate Complexes
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Various carboxylic acids were directly transformed into the corresponding ketones by utilizing organozinc ate complexes, which provide high chemoselectivity without any overreaction to the undesired tertiary carbinol, owing to formation of a stable tetrahedral zincioketal intermediate. This method offers good overall atom/step/pot economy and operational simplicity. 相似文献
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Hongchao Zheng Robert McDonald Dr. Dennis G. Hall Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(18):5454-5460
Herein, the concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied in several classic dipolar [3+2] cycloadditions involving azides, nitrile oxides, and nitrones as partners. These cycloadditions can be used to produce pharmaceutically interesting, small heterocyclic products, such as triazoles, isoxazoles, and isoxazolidines. These cycloadducts are formed directly and include a free carboxylic acid functionality that can be employed for further transformations, thereby avoiding prior masking or functionalization. In all cases, BAC provides faster reactions, under milder conditions, with much improved product yields and regioselectivities. In some instances, such as triazole formation from the reaction of azides with 2‐alkynoic acids, catalysis with ortho‐nitrophenylboronic acid circumvents the undesirable product decarboxylation observed when using thermal activation. By using NMR spectroscopic studies, the boronic acid catalyst was shown to provide activation by a LUMO‐lowering effect in the unsaturated carboxylic acid, likely via a monoacylated hemiboronic ester intermediate. 相似文献
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综述了钯催化的酸酐碳—氧键的活化和反应 ,及由羧酸直接制备相应的醛、酮且不需要卤原子和碱参与的方法 相似文献
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Takahiro Horibe Takashi Hazeyama Yuto Nakata Kazuki Takeda Kazuaki Ishihara 《Angewandte Chemie (International ed. in English)》2020,59(39):17256-17260
An enantioselective 1,4‐addition of α,β‐unsaturated carboxylic acids with cycloalkanones has been developed by using chiral amine–boronic acid cooperative catalysts. In the presence of a chiral amine and boronic acid, cycloalkanones and carboxylic acids are activated as chiral enamines and mixed anhydrides, respectively. The corresponding 1,4‐adducts are obtained in high yield with high enantioselectivity. Furthermore, subsequent oxylactonization of the 1,4‐adducts gives spirolactones with high diastereoselectivity. 相似文献
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