Palladium(II)-Catalyzed Deacylative Allylic C–H Alkylation

The first deacylative allylic C–H alkylation has been established by employing the palladium-catalyzed allylic C–H activation and decarboxylative nucleophile generation. A wide scope of nucleophiles are tolerated and densely functionalized alkylation products turn out to be furnished in moderate to good yield. More importantly, this strategy provides an alternative method for the allylic C–H alkylation with less stabilized carbon nucleophiles, and can be further expanded to the synthesis of unconjugated enynes

An Organocatalytic Asymmetric Allylic Alkylation Allows Enantioselective Total Synthesis of Hydroxymetasequirin‑A and Metasequirin‑B Tetramethyl Ether Diacetates

The first highly stereoselective organocatalytic intermolecular allylic alkylation of allylic alcohols with 1,3-dicarbonyls has been developed to allow the first enantioselective total synthesis of hydroxymetasequirin-A and metasequirin-B tetramethyl ether diacetates

An Organocatalytic Asymmetric Allylic Alkylation Allows Enantioselective Total Synthesis of Hydroxymetasequirin‑A and Metasequirin‑B Tetramethyl Ether Diacetates

The first highly stereoselective organocatalytic intermolecular allylic alkylation of allylic alcohols with 1,3-dicarbonyls has been developed to allow the first enantioselective total synthesis of hydroxymetasequirin-A and metasequirin-B tetramethyl ether diacetates

Palladium(II)/Lewis Acid Synergistically Catalyzed Allylic C–H Olefination

The first allylic C–H olefination with α-diazo esters synergistically catalyzed by a palladium­(II) complex and (salen)­CrCl has been established to directly generate conjugated polyene derivatives in moderate to high yields and with excellent stereoselectivities

Enantioselective Functionalization of Inactive sp³ C–H Bonds Remote to Functional Group by Metal/Organo Cooperative Catalysis

A metal/organo cooperative catalysis to enable the enantioselective functionalization of inactive C–H bonds γ to the formyl group in aliphatic aldehydes has been established. Instead of using enals as substrates in traditional organocatalytic cyclization reactions, the aliphatic aldehydes directly participated in [4 + 2] cyclization with quinone derivatives exploiting molecular oxygen as oxidants to afford optically active cyclic molecules with excellent levels of enantioselectivity. This method features a combination of pot, step, and atom economy

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

The hybrid Au­(I)/Brønsted 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 <i>N</i>-triflyl phosphoramide

Enantioselective Synthesis of 5‑Alkylated Thiazolidinones via Palladium-Catalyzed Asymmetric Allylic C–H Alkylations of 1,4-Pentadienes with 5<i>H</i>‑Thiazol-4-ones

A palladium-catalyzed, enantioselective allylic C–H alkylation of 1,4-pentadienes with 5<i>H</i>-thiazol-4-ones has been developed. Under the cooperative catalysis of a palladium complex of chiral phosphoramidite ligand and an achiral Brønsted acid, a broad range of substituted 5<i>H</i>-thiazol-4-ones bearing sulfur-containing tertiary chiral centers were accessed from the allylic C–H alkylation in high levels of yields and enantioselectivities. Alkyl and aryl 1,4-pentadienes led to linear and branched allylation products, respectively

Asymmetric Allylic C–H Oxidation for the Synthesis of Chromans

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

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

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 Brønsted 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 beneficial to the allylic C–H oxidation due to their survival in the presence of quinone derivative oxidants. These allylic C–H alkylation reactions undergo smoothly under mild conditions and tolerate a wide range of substrates. The resultant highly functionalized chiral pyrazol-5-ones have been applied to the preparation of more structurally diverse heterocycles by classical transformations

Asymmetric α‑Allylation of Aldehydes with Alkynes by Integrating Chiral Hydridopalladium and Enamine Catalysis

A palladium-catalyzed asymmetric α-allylation of aldehydes with alkynes has been established by integrating the catalysis of enamine and chiral hydridopalladium complex that is reversibly formed from the oxidative addition of Pd(0) to chiral phosphoric acid. The ternary catalyst system, consisting of an achiral palladium complex, a primary amine, and a chiral phosphoric acid allows the reaction to tolerate a wide scope of α,α-disubstituted aldehydes and alkynes, affording the corresponding allylation products in high yields and with excellent levels of enantioselectivity