Silver-Catalyzed Carbamoylation and Carbonylative Cyclization of Alkenes with Oxamic Acids.

Transition metal-catalyzed carbonylation functionalization reaction of alkenes is an attractive research area in modern organic chemistry. However, there have been very few reports on silver-catalyzed reactions in carbonylation reactions. Herein we developed a silver-catalyzed carbamoylation and carbonylative cyclization of alkenes with oxamic acids to obtain 2-acetylamino-1-tetralone derivatives. Various desired cyclized products were formed in moderate to good yields through radical intermediates.

Nickel-Catalyzed Four-Component Carbonylation of 1,3-Butadiene To Access ß,γ-Unsaturated Ketones.

A new strategy to obtain ß,γ-unsaturated ketones via the cross-coupling of 1,3-butadiene, alkyl bromides, and arylboronic acids under 1 bar of CO with nickel as the catalyst has been developed. This newly developed four-component carbonylation procedure features advantages including using a cheap catalytic system, high step economy, mild reaction conditions, and excellent 1,4-regioselectivity, thereby providing a sustainable and alternative tool for ß,γ-unsaturated ketones production compared to the present tactics. To elucidate the application potential of this method, olefin synthons are derived from the representative coupling product.

Photoredox-catalyzed carbonylative acylation of styrenes with Hantzsch esters.

Ketones exist widely in naturally occurring products and are indispensable building blocks in organic synthesis. Carbonylation represents one of the most straightforward methods for ketone preparation and has become an attractive field in modern organic chemistry as well. Among the strategies, photocatalytic carbonylation is also worthy of further exploration. Herein, we developed a three-component carbonylation that provides a new method for the synthesis of ketones from Hantzsch esters, CO and styrenes. The reaction was performed under a blue light environment and yields a series of ketones with moderate to good yields.

Site-selective carbonylation of arenes via C(sp2)-H thianthrenation: direct access to 1,2-diarylethanones.

Herein, a new reaction for the site-selective carbonylation of arenes via C(sp2)-H thianthrenation under mild conditions has been developed. With low loadings of palladium catalysts, various desired 1,2-diarylethanones are produced in good yields. This strategy also enables the late-stage modification of complex molecules, which was previously challenging with similar carbonylative Negishi-type reactions.

Copper-Catalyzed Direct Carbonylation of Carbenes toward the Synthesis of Propanedioic Acid Derivatives.

Carbenes are highly active reaction intermediates, which can be used as reaction precursors to modify organisms, drugs, and material molecules. In this work, we realized a new cheap metal-catalyzed carbonylation of carbene to give propanedioic acid derivatives. With copper salt as the catalyst, synthetically important malonates and related compounds were produced in good yields under mild reaction conditions.

Palladium-Catalyzed Direct Carbonylation of Bromoacetonitrile to Synthesize 2-Cyano-N-acetamide and 2-Cyanoacetate Compounds.

Nitrile compounds containing ester and amide groups are important functionalized chemicals in synthetic and medicinal chemistry. In this article, an efficient and convenient palladium-catalyzed carbonylative procedure toward 2-cyano-N-acetamide and 2-cyanoacetate compounds has been developed. The reaction proceeds under mild conditions via radical intermediate which is suitable for late-stage functionalization. Gram-scale experiment was performed successfully under low catalyst loading and gave the target product in excellent yield. Additionally, this transformation can be performed under atmospheric pressure and provide alternative routes to 7 drug precursors.

Palladium-catalyzed difluoroalkylative carbonylation of styrenes toward difluoropentanedioates.

The introduction of fluorine atoms into organic molecules is an attractive but challenging topic. In this work, an interesting palladium-catalyzed difluoroalkylative carbonylation of aryl olefins has been developed. A wide range of aryl olefins were transformed into the corresponding difluoropentanedioate compounds with good functional-group tolerance and excellent regioselectivity. Inexpensive ethyl bromodifluoroacetate acts both as a difluoroalkyl precursor and a nucleophile here. Additionally, a scale-up reaction was also performed successfully, and further transformations of the obtained product were shown as well.

Palladium-Catalyzed Perfluoroalkylative Carbonylation of 2-Allylaryl Trifluoromethanesulfonates: Base-Controlled Selective Access to ß-Perfluoroalkyl Amides.

A palladium-catalyzed perfluoroalkylative carbonylation of 2-allylaryl trifluoromethanesulfonates has been developed. A range of 2-allyl trifluoromethanesulfonates, perfluoroalkyl halides, and amines were applied in this tandem procedure to provide the corresponding ß-perfluoroalkyl amides with good functional group tolerance and high chemoselectivity. The final products were controlled by the base applied.

Palladium-Catalyzed Carbonylation of Disulfides and Ethylene: Synthesis of ß-Thiopropionate Thioesters.

Transforming carbon monoxide (C1) and ethylene (C2) into high value-added chemicals is of great significance from an economic perspective, especially to multifunctionalized C3 compounds. Herein, we developed a palladium-catalyzed thiocarbonylative 1,2-difunctionalization of ethylene. Employing NiXantPhos as the ligand and DCE as the solvent, a series of organic disulfides can be successfully transformed into ß-thiopropionate thioesters in good yields.

Nickel-Catalyzed One-Pot Carbonylative Synthesis of 2-Mono- and 2,3-Disubstituted Thiochromenones from 2-Bromobenzenesulfonyl Chlorides and Alkynes.

A nickel-catalyzed one-pot carbonylation reaction of 2-bromobenzenesulfonyl chlorides with alkynes for the synthesis of thiochromenones has been established. Both terminal and internal alkynes were suitable substrates in this carbonylative transformation, and a broad range of 2-mono- and 2,3-disubstituted thiochromenone products were obtained in moderate to good yields with quite high functional group compatibility. Notably, this procedure presents the first example of nickel-catalyzed carbonylative synthesis of thiochromenones with 2-bromobenzenesulfonyl chlorides as a promising sulfur precursor.

A novel construction of acetamides from rhodium-catalyzed aminocarbonylation of DMC with nitro compounds.

Dimethyl carbonate (DMC), an environment-friendly compound prepared from CO2, shows diverse reactivities. In this communication, an efficient procedure using DMC as both a C1 building block and solvent in the aminocarbonylation reaction with nitro compounds has been developed. W(CO)6 acts both a CO source and a reductant here.

Nickel-Catalyzed Thiocarbonylation of Arylboronic Acids with Sulfonyl Chlorides for the Synthesis of Thioesters.

An interesting procedure for thioester synthesis via nickel-catalyzed thiocarbonylation of arylboronic acid with sulfonyl chlorides as the sulfur source has been explored. Using Mo(CO)6 as a solid CO surrogate and reductant, a broad range of thioesters were obtained in moderate to good yields with good functional group tolerance.