Recent developments in palladium-catalyzed C–S bond formation

Organic Chemistry Frontiers, Journal Year: 2020, Volume and Issue: 7(11), P. 1395 - 1417

Published: Jan. 1, 2020

This review summarized the recent developments in palladium-catalyzed C–S bond formation involving sulfenylation and sulfonylation reactions.

Language: Английский

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Palladium-Catalyzed meta-C–H Allylation of Arenes: A Unique Combination of a Pyrimidine-Based Template and Hexafluoroisopropanol

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(28), P. 12453 - 12466

Published: June 4, 2020

Controlling remote selectivity and delivering novel functionalities at distal positions in arenes are an important endeavor contemporary organic synthesis. In this vein, template engineering mechanistic understanding of new functionalization strategies essential for enhancing the scope such methods. Herein, meta-C–H allylation has been achieved with aid a palladium catalyst, pyrimidine-based auxiliary, allyl phosphate. 1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) was found as critical solvent transformation. The role HFIP throughout catalytic cycle systematically studied. A broad substrate phenethyl ether, phenol, benzylsulfonyl ester, phenethylsulfonyl phenylacetic acid, hydrocinnamic 2-phenylbenzoic acid derivatives demonstrated. Interestingly, conformationally flexible have also selectively allylated meta-position using combination 1H NMR, 31P ESI-MS, kinetic experiments, density functional theory (DFT) computations suggested that reaction proceeds through ligand-assisted activation, addition forming Pd-π-allyl complex which is then followed by turnover determining C–C bond formation step leading to meta-allylated product.

Language: Английский

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Rhodium‐Catalyzed Enantioselective Oxidative [3+2] Annulation of Arenes and Azabicyclic Olefins through Twofold C−H Activation

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(49), P. 17666 - 17670

Published: Sept. 24, 2019

Abstract C−H bond activation is mostly limited to ortho selectivity. Activation of both and meta bonds constitutes a particularly important strategy for annulation, but has rarely been studied in enantioselective systems. Reported herein rhodium(III)‐catalyzed asymmetric [3+2] transannulation arenes with 7‐azabenzonorbornadienes. Two distinct classes have identified as substrates, the coupling proceeded high enantioselectivity excellent diastereoselectivity through sequential bonds.

Language: Английский

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Recent advances in Rh(iii)/Ir(iii)-catalyzed C–H functionalization/annulation via carbene migratory insertion

Organic & Biomolecular Chemistry, Journal Year: 2021, Volume and Issue: 19(7), P. 1438 - 1458

Published: Jan. 1, 2021

The review highlighted diverse annulations, including nitrogen, oxygen, sulfur heterocycles and carbocylizations via Rh(iii)/Ir(iii)-catalyzed C–H functionalization/annulation with various arene carbene precursors.

Language: Английский

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Regiospecific ortho‐C−H Allylation of Benzoic Acids

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(44), P. 14580 - 14584

Published: Feb. 7, 2018

A carboxylate-directed ortho-C-H functionalization has been developed and it allows the regiospecific introduction of allyl residues to benzoic acids. In presence a [Ru(p-cymene)Cl2 ]2 K3 PO4 , acids react with acetates at only 50 °C give corresponding ortho-allylbenzoic The protocol is generally applicable both electron-rich electron-poor in combination linear branched acetates. products can be further functionalized situ, for example, by double-bond migration, lactonization, or decarboxylation.

Language: Английский

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Rh(III)-Catalyzed and Solvent-Controlled Chemoselective Synthesis of Chalcone and Benzofuran Frameworks via Synergistic Dual Directing Groups Enabled Regioselective C–H Functionalization: A Combined Experimental and Computational Study

ACS Catalysis, Journal Year: 2018, Volume and Issue: 8(10), P. 9508 - 9519

Published: Sept. 5, 2018

By virtue of a synergistically dual-directing-group (the O–NHAc part and the hydroxyl group)-assisted strategy, efficient practical Rh(III)-catalyzed regioselective redox-neutral C–H functionalization diverse N-phenoxyacetamides with propargyl alcohols has been realized, which led to divergent synthesis privileged benzofuran chalcone frameworks in solvent-controlled chemoselective manner. Experimental computational studies reveal that formation hydrogen bonding between dual directing groups subsequent coordination interaction group Rh(III) catalyst play decisive role promoting migratory insertion alkyne moiety. Thereafter, two switchable reaction pathways, respectively involve tandem β–H elimination/hydrogen transfer/oxidative addition/C–O bond reductive elimination/oxidation (for low-polar solvents: path I–Ia via RhIII–RhI–RhIII pathway) oxidative addition/β–H transfer/protonolysis high-polar II–IIb RhIII–RhV–RhIII pathway), are followed deliver corresponding products excellent chemoselectivity. Taken together, our results presented here not only give an expansion area O–NHAc-directed activations but also provide rational basis for future development synergistic DGs-enabled reactions.

Language: Английский

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Rhodium Catalyzed Regioselective C−H Allylation of Simple Arenes via C−C Bond Activation of Gem‐difluorinated Cyclopropanes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(19), P. 10626 - 10631

Published: Feb. 18, 2021

Herein, we report a rhodium catalyzed directing-group free regioselective C-H allylation of simple arenes. Readily available gem-difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via sequence C-C and C-F bond activation, providing arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late-stage functionalization complex bioactive molecules. efficiency this reaction is also demonstrated by the turnover number (TON, up to 1700) catalyst on gram-scale experiments. Preliminary success kinetic resolution transformation achieved, promising access enantio-enriched cyclopropanes.

Language: Английский

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Palladium‐Catalyzed Directed meta‐Selective C−H Allylation of Arenes: Unactivated Internal Olefins as Allyl Surrogates

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(30), P. 10353 - 10360

Published: May 24, 2019

Abstract Palladium(II)‐catalyzed meta ‐selective C−H allylation of arenes has been developed utilizing synthetically inert unactivated acyclic internal olefins as allylic surrogates. The strong σ‐donating and π‐accepting ability pyrimidine‐based directing group facilitates the olefin insertion by overcoming inertness typical olefins. Exclusive allyl over styrenyl product selectivity well E stereoselectivity were achieved with broad substrate scope, wide functional‐group tolerance, good to excellent yields. Late‐stage functionalisations pharmaceuticals demonstrated. Experimental computational studies shed light on mechanism point key steric control in palladacycle, thus determining selectivities.

Language: Английский

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TEMPO in metal complex catalysis

Coordination Chemistry Reviews, Journal Year: 2020, Volume and Issue: 423, P. 213482 - 213482

Published: July 27, 2020

Language: Английский

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Copper-Catalyzed Direct C–H Alkylation of Polyfluoroarenes by Using Hydrocarbons as an Alkylating Source

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(16), P. 7487 - 7496

Published: April 1, 2020

Construction of carbon–carbon bonds is one the most important tools in chemical synthesis. In previously established cross-coupling reactions, prefunctionalized starting materials were usually employed form aryl or alkyl (pseudo)halides their metalated derivatives. However, direct use arenes and alkanes via a 2-fold oxidative C–H bond activation strategy to access chemoselective C(sp2)–C(sp3) cross-couplings highly challenging due low reactivity carbon–hydrogen (C–H) difficulty suppressing side reactions such as homocouplings. Herein, we present new development copper-catalyzed cross-dehydrogenative coupling polyfluoroarenes with under mild conditions. Relatively weak sp3 at benzylic allylic positions, nonactivated hydrocarbons could be alkylated by newly developed catalyst system. A moderate-to-high site selectivity was observed among various hydrocarbon reactants, including gaseous feedstocks complex molecules. Mechanistic information obtained performing combined experimental computational studies reveal that copper plays dual role activating both alkane sp2 polyfluoroarene bonds. It also suggested noncovalent π–π interaction hydrogen formed situ between optimal ligand arene substrates are key facilitating current reactions.

Language: Английский

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