Palladium-Catalyzed Asymmetric Allylic C–H Functionalization: Mechanism, Stereo- and Regioselectivities, and Synthetic Applications

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(12), P. 2841 - 2854

Published: Oct. 2, 2020

ConspectusAsymmetric functionalization of inert C–H bonds is undoubtedly a synthetically significant yet challenging bond-forming process, allowing for the preparation densely functionalized molecules from abundantly available feedstocks. In past decade, our group and others have found that trivalent phosphorus ligands are capable facilitating Pd-catalyzed allylic α-alkenes upon using p-quinone as an oxidant. these reactions, 16-electron Pd(0) complex bearing monodentate ligand, p-quinone, α-alkene has been identified key intermediate. Through concerted proton two-electron transfer electrophilic π-allylpalladium subsequently generated can be leveraged to forge versatile chemical with wide range nucleophiles. This Account focuses on describing origin, evolution, synthetic applications asymmetric emphasis fundamental mechanism process in activation.Enabled by cooperative catalysis palladium triarylphosphine, primary amine, chiral phosphoric acid, enantioselective α-allylation aldehydes established. The combination acid phosphoramidite ligand allows alkylation pyrazol-5-ones give excellent enantioselectivities, wherein synergistically control stereoselectivity. Notably, palladium–phosphoramidite complexes also efficient catalysts alkylation, scope case 1,4-dienes, geometry coordination pattern nucleophile able vary transition states events thereby determine Z/E-, regio-, stereoselectivities.These reactions tolerant nucleophiles α-alkenes, providing large library optically active building blocks. Based intramolecular oxidation, formal synthesis (+)-diversonol accomplished, amination enable concise access letermovir. particular, 1,4-dienes azlactones offers highly enantioenriched α,α-disubstituted α-amino derivatives serving blocks lepadiformine alkaloids. addition, tachykinin receptor antagonist (−)-tanikolide synthesized corresponding reactions.

Language: Английский

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Applications of Nanomaterials in Asymmetric Photocatalysis: Recent Progress, Challenges, and Opportunities

Advanced Materials, Journal Year: 2020, Volume and Issue: 33(6)

Published: July 16, 2020

Abstract Asymmetric catalysis is one of the most attractive strategies to obtain important enantiomerically pure chemicals with high quality and production. In addition, thanks abundant sustainable advantages solar energy, photocatalysis possesses great potential in environmentally benign reactions. Undoubtedly, asymmetric meets strict demand modern chemistry: friendly energy‐sustainable alternatives. Compared homogeneous photocatalysis, heterogeneous has features easy separation, recovery, reuse merits, thus being cost‐ time‐effective. Herein, state‐of‐the‐art progress by nanomaterials addressed. The discussion comprises two sections based on type nanomaterials: typical inorganic semiconductors like TiO 2 quantum dots emerging porous materials including metal–organic frameworks, organic polymers, cages. Finally, challenges future developments are proposed.

Language: Английский

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Rhodium-Catalyzed Atroposelective Oxidative C–H/C–H Cross-Coupling Reaction of 1-Aryl Isoquinoline Derivatives with Electron-Rich Heteroarenes

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(37), P. 15678 - 15685

Published: Aug. 31, 2020

Rhodium(III)-catalyzed enantioselective oxidative C–H/C–H cross-coupling reaction between two arenes is disclosed. With the combination of a chiral CpRh(III) complex and carboxylic acid additive, direct coupling reactions 1-aryl isoquinoline derivatives electron-rich heteroarenes such as thiophenes, furans, benzothiophenes, benzofurans are realized via double C–H functionalization process. A series axially compounds obtained in excellent yields enantioselectivities (up to 99% yield ee). Mechanistic studies suggest that both bond cleavages may not be turnover-limiting step.

Language: Английский

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Iridium-catalyzed Z -retentive asymmetric allylic substitution reactions

Science, Journal Year: 2021, Volume and Issue: 371(6527), P. 380 - 386

Published: Jan. 21, 2021

Keeping Z -olefins intact with iridium Transition metal catalysis offers a versatile means of modifying carbon centers adjacent to carbon-carbon double bonds. However, in the course these reactions, bond tends get weakened, allowing its substituents swivel back and forth. Thus, if two large groups start out on same side axis (a geometry known as -olefin), they end up opposite sides product. Jiang et al. report chiral catalyst that prevents this swiveling just long enough substitute enantioselectively (see Perspective by Malcolmson). Science , issue p. 380 ; see also 345

Language: Английский

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Bimetallic Catalysis in Stereodivergent Synthesis

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(45)

Published: Aug. 2, 2022

Abstract Bimetallic catalysis has emerged as an efficient strategy for the development of new chemical reactions. Importantly, this also provides a simple and powerful platform stereodivergent synthesis, whereby all possible stereoisomers products bearing two stereocenters can be easily prepared from same set starting materials. In Minireview, allylic substitution, propargylic hydrofunctionalization, annulation based on bimetallic been summarized. It is expected that more catalytic systems will developed applied synthesis valuable molecules.

Language: Английский

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