Nickel-Catalyzed Reductive Aryl Thiocarbonylation of Alkene via Thioester Group Transfer Strategy

Visible-Light-Mediated Synthesis of Thioesters Using Thiocarboxylic Acid as the Dual Reagent

We have developed a visible-light-driven method for thioester synthesis that relies on the unique dual role of thiobenzoic acids as one-electron reducing agents and reactants leading to the formation of sulfur radical species. This synthetic process offers a wide scope, accommodating various thioacid and thiol substrates without the need for a photocatalyst.

Nickel-Catalyzed Reductive Dicarbofunctionalizations of Alkenes for the Synthesis of Difluorocarbonyl Oxindoles and Isoquinoline-1,3-diones

A novel and efficient strategy for the construction of difluorocarbonyl-oxindole and difluorocarbonyl-isoquinoline-1,3-dione derivatives involving nickel-catalyzed intramolecular Heck-type cyclizations followed by intermolecular cross-couplings has been developed. This approach features high functional group tolerance, broad substrate scope, and operational simplicity under mild conditions, thus providing a new method for the rapid difluorocarbonyl-functionalization of alkenes to construct the structurally diversified five- and six-membered heterocycles.

Divergent Acyl and Decarbonylative Liebeskind-Srogl Cross-Coupling of Thioesters by Cu-Cofactor and Pd-NHC (NHC = N-Heterocyclic Carbene) Catalysis

Transition-metal-catalyzed cross-coupling reactions of thioesters by selective acyl C(O)-S cleavage have emerged as a powerful platform for the preparation of complex molecules. Herein, we report divergent Liebeskind-Srogl cross-coupling of thioesters by Pd-NHC (NHC = N-heterocyclic carbene) catalysis. The reaction provides straightforward access to functionalized ketones by highly selective C(acyl)-S cleavage under mild conditions. Most crucially, the conditions enable direct functionalization of a range of complex pharmaceuticals decorated with a palette of sensitive functional groups, providing attractive products for medicinal chemistry programs. Furthermore, decarbonylative Liebeskind-Srogl cross-coupling by C(acyl)-S/C(aryl)-C(O) cleavage is reported. Cu metal cofactor directs the reaction pathway to acyl or decarbonylative pathway. This reactivity is applicable to complex pharmaceuticals. The reaction represents the mildest decarbonylative Suzuki cross-coupling discovered to date. The Cu-directed divergent acyl and decarbonylative cross-coupling of thioesters opens up chemical space in complex molecule synthesis.

Palladium-Catalyzed Thiocarbonylation of Aryl Iodides with S-Aryl Thioformates via Thioester Transfer

Herein we reported a novel approach to synthesize thioesters with S-aryl thioformates as thioester sources. The reaction proceeded at ambient temperature using widely available starting ingredients, wherein the thioester moiety was smoothly transferred to aryl iodides from S-aryl thioformates. A variety of substrates with various electronic natures were all tolerated under the reaction conditions to furnish desirable thioesters in ranges from moderate to excellent yields. The gram-scale reaction was also conducted, and there was virtually little change in chemical yield, indicating that large-scale synthesis of thioesters may be viable using this method.

Nickel-catalyzed Thioester Transfer Reaction with sp2-Hybridized Electrophiles

We report a thioacylation transfer reaction based on nickel-catalyzed C-C bond cleavage of thioesters with sp²-hybridized electrophiles. Aryl bromides, iodides, and alkenyl triflates can participate in thioester transfer reaction of aryl thioesters, affording a wide range of structurally diverse new thioesters in yields of up to 98% under mild reaction conditions. With this protocol, it is possible to construct alkenyl thioesters from the corresponding ketones through the generation of alkenyl triflates.

Palladium-Catalyzed Thiocarbonylations with TIPS Thioethers

Herein, we describe a palladium-catalyzed thiocarbonylation via the reaction of a σ-alkyl palladium intermediate with carbon monoxide (CO) and a TIPS thioether. The use of CsF, (IPr)Pd(allyl)Cl, CO, and a TIPS thioether in THF are key to obtaining alkyl and aryl thioesters in high yields. The yield of the palladium-catalyzed thiocarbonylation depends on the structure of substrate and it was observed that indoline-2-one derivatives were formed faster than indoline derivatives. The reactions of benzoyl and hydrocinnamoyl fluorides with PhSTIPS and CsF were also demonstrated to form the corresponding thioesters.

Metal-free photocleavage of C(non-acyl)-S bond of thioesters for regioselective pyridylthioesterification of styrenes

Transformation of thioesters via transition-metal-mediated C(acyl)−S bond cleavage is an emerging method to forge C-C and C-heteroatom bonds. Herein, we report the first activation of stronger C(non-acyl)–S bond of thioesters...

“Thiol-free synthesized” and sustainable thiolating synthons for nickel-catalyzed reductive assembly of sulfides with high efficiency

Unsymmetrical sulfides are widely found in the pharmaceutical industry, organic synthesis, and materials science.

Nickel-Catalyzed Multicomponent Coupling: Synthesis of α-Chiral Ketones by Reductive Hydrocarbonylation of Alkenes

A nickel-catalyzed, multicomponent regio- and enantioselective coupling via sequential hydroformylation and carbonylation from readily available starting materials has been developed. This modular multicomponent hydrofunctionalization strategy enables the straightforward reductive hydrocarbonylation of a broad range of unactivated alkenes to produce a wide variety of unsymmetrical dialkyl ketones bearing a functionalized α-stereocenter, including enantioenriched chiral α-aryl ketones and α-amino ketones. It uses chiral bisoxazoline as a ligand, silane as a reductant, chloroformate as a safe CO source, and a racemic secondary benzyl chloride or an N-hydroxyphthalimide (NHP) ester of a protected α-amino acid as the alkylation reagent. The benign nature of this process renders this method suitable for late-stage functionalization of complex molecules.

Palladium Catalyzed Direct Carbonylative Thiomethylation of Aryldiazonium Salts and Amines with 4-(Methylthio)-2-Butanone as (Methylthio) Transfer Agent

Herein, an interesting palladium-catalyzed procedure for the direct carbonylative thiomethylation of aromatic amine derivatives with 4-methylthio-2-butanone is developed. Using 4-methylthio-2-butanone as (methylthio) transfer agent, a variety of corresponding thioesters are obtained with moderate to good yields under base-free condition. In addition, good functional group tolerance can be observed.

Palladium-Catalyzed Aryl-Furanylation of Alkenes: Synthesis of Benzofuran-Containing 3,3-Disubstituted Oxindoles

A novel palladium-catalyzed aryl-furanylation of alkenes is described. This protocol provided a straightforward route to the synthesis of various benzofuran-containing 3,3-disubstitutedoxindole derivatives bearing a quarternary carbon center. In the cascade process, one C(sp²)-O bond, two C(sp²)-C(sp³) bonds, an oxindole, and a furan ring are formed in a single chemical operation.

Nickel-catalyzed carbonylation of thioacetates with aryl iodides via CO insertion and C–S bond cleavage

Aryl thioesters are synthesized via nickel-catalyzed carbonylation of thioacetates with aryl iodides. Alkyl thioacetates undergo coupling with carbon monoxide and aryl iodides to produce the desired aryl thioesters in moderate yields. This catalytic carbonylative coupling process provides a cost-effective and direct approach for the preparation of useful thioesters.

Ni-Catalyzed Cross-Electrophile Coupling of Aryl Triflates with Thiocarbonates via C-O/C-O Bond Cleavage

A nickel-catalyzed reductive coupling of aryl triflates with thiocarbonates is reported here. Both electron-rich and -deficient aryl C(sp²)-O electrophiles as well as a class of O-tBu S-alkyl thiocarbonates are compatible with the optimized reaction conditions, as evidenced by 49 examples. The reaction also proceeds with good chemoselective cleavage of the C-O bond with regard to thioesters. This work broadens the scope of nickel-catalyzed reductive cross-electrophile coupling reactions.

Intermolecular alkene arylcyanation using BnSCN as a cyanide source via a reductive strategy: access to 3,3-disubstituted oxindoles

Herein, a nickel-catalyzed two-component reductive arylcyanation of aryl (pseudo)halide tethered alkenes using benzyl thiocyanate as a cyanide source via C–S bond activation is developed.