Pu-Sheng Wang

Bio: Pu-Sheng Wang is an academic researcher from University of Science and Technology of China. The author has contributed to research in topics: Allylic rearrangement & Enantioselective synthesis. The author has an hindex of 18, co-authored 43 publications receiving 1108 citations.

Chiral Counteranion Strategy for Asymmetric Oxidative C(sp3)H/C(sp3)H Coupling: Enantioselective α‐Allylation of Aldehydes with Terminal Alkenes

Abstract: The first enantioselective α-allylation of aldehydes with terminal alkenes has been realized by combining asymmetric counteranion catalysis and palladium-catalyzed allylic C-H activation. This method can tolerate a wide scope of α-branched aromatic aldehydes and terminal alkenes, thus affording allylation products in high yields and with good to excellent levels of enantioselectivity. Importantly, the findings suggest a new strategy for the future creation of enantioselective C-H/C-H coupling reactions.

Hybrid Metal/Organo Relay Catalysis Enables Enynes To Be Latent Dienes for Asymmetric Diels–Alder Reaction

Abstract: The hybrid Au(I)/Bronsted acid binary catalyst system enables enynes to serve as latent 1,3-silyloxydienes capable of participating in the first cascade hydrosiloxylation of an enynyl silanol/asymmetric Diels–Alder reaction. A variety of polycyclic compounds bearing multistereogenic centers were obtained in high yields and excellent enantioselectivities from the relay catalytic cascade reaction between (2-(but-3-en-1-ynyl)phenyl) silanols and quinones catalyzed by the combined achiral gold complex and chiral N-triflyl phosphoramide.

Highly Enantioselective Allylic C–H Alkylation of Terminal Olefins with Pyrazol-5-ones Enabled by Cooperative Catalysis of Palladium Complex and Brønsted Acid

Abstract: A highly enantioselective allylic C–H alkylation reaction of allylarenes with pyrazol-5-ones has been established by the cooperative catalysis of a chiral palladium complex and chiral Bronsted acid to afford a wide spectrum of functionalized chiral N-heterocycles with an all-carbon quaternary stereogenic center in high yields and with high levels of enantioselectivity (up to 96% ee), wherein the chiral ligand and phosphoric acid showed synergistic effect on the control of stereoselectivity. In addition, a palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-pentadienes with pyrazol-5-ones has been realized to furnish highly functionalized pyrazol-5-ones in high enantioselectivities. In this case, the chiral ligand controls the stereoselectivity while the achiral Bronsted acid, 2-fluorobenzoic acid, turns out to be a better cocatalyst than the chiral phosphoric acid. The installation of electron-deficient substituents at 3,3′-positions of binaphthyl backbone of chiral phosphoramidites is actually b...

Asymmetric Allylic C–H Oxidation for the Synthesis of Chromans

Abstract: An enantioselective intramolecular allylic C–H oxidation to generate optically active chromans has been accomplished under the cooperative catalysis of a palladium complex of chiral phosphoramidite ligand and 2-fluorobenzoic acid. Mechanistic studies suggest that this reaction commences with a Pd-catalyzed allylic C–H activation event and then undergoes asymmetric allylic alkoxylation. The synthetic significance of the method has been embodied by concisely building up a key chiral intermediate to access (+)-diversonol.

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

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

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Abstract: Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C–C single bond or C═C double bond formations in transition-metal-catalyzed reactions. This type of coupling reaction involves the following general steps. First, the organometallic species is generated by various processes, including oxidative addition, transmetalation, cyclization, C–C bond cleavage, and C–H bond activation. Subsequently, the organometallic species reacts with the diazo substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion to form a C–C bond. The new organometallic species generated from migratory insertion may undergo various transformations. This type of carbene-based coupling has proven...

Asymmetric Counteranion-Directed Catalysis: Concept, Definition, and Applications

Abstract: Recently, the use of enantiomerically pure counteranions for the induction of asymmetry in reactions proceeding through cationic intermediates has emerged as an exciting new concept, which has been termed asymmetric counteranion-directed catalysis (ACDC). Despite its success, the concept has not been fully defined and systematically discussed to date. This Review closes this gap by providing a clear definition of ACDC and by examining both clear cases as well as more ambiguous examples to illustrate the differences and overlaps with other catalysis concepts.

Catalytic Enantioselective Transformations Involving C-H Bond Cleavage by Transition-Metal Complexes.

Abstract: The development of new methods for the direct functionalization of unactivated C–H bonds is ushering in a paradigm shift in the field of retrosynthetic analysis. In particular, the catalytic enantioselective functionalization of C–H bonds represents a highly atom- and step-economic approach toward the generation of structural complexity. However, as a result of their ubiquity and low reactivity, controlling both the chemo- and stereoselectivity of such processes constitutes a significant challenge. Herein we comprehensively review all asymmetric transition-metal-catalyzed methodologies that are believed to proceed via an inner-sphere-type mechanism, with an emphasis on the nature of stereochemistry generation. Our analysis serves to document the considerable and rapid progress within in the field, while also highlighting limitations of current methods.

Combining transition metal catalysis and organocatalysis--an update.

Abstract: The combination of transition metal catalysis and organocatalysis as a new and exciting research area has attracted increasing attention as it can enable the development of unprecedented transformations that is not possible by use of either of the catalytic systems alone, and can improve the reactivity, efficiency and stereocontrol of existing chemical transformations. In this review, we summarize recent remarkable progress in the field of combined transition metal catalysis and organocatalysis, further highlighting the potential of this new and exciting research area and the many challenges that still remain for the future.