Copper-Mediated Decarboxylative Coupling between Arylacetic Acids and 1,3-Dicarbonyl Compounds

Copper-Mediated Decarboxylative Coupling of 3-Indoleacetic Acids with Sulfoxonium Ylides for the Synthesis of α-Acetoxyl Ketones

The most convenient and direct method of synthesizing an α-acyloxy ketone is the reaction of a diazo compound with a carboxylic acid via O-H insertion. However, due to the limitations in preparing and storing diazo compounds, the application of this method is restricted. In this study, Cu(OAc)2-mediated (OAc = acetate) decarboxylative coupling reactions of 3-indoleacetic acids with sulfoxonium ylides were developed for use in rapidly synthesizing α-acetoxyl ketones. In this reaction, Cu(OAc)2 was not only used as an oxidant, but also as acetate ion source. Notably, when 5-methoxy-2-methyl-3-indoleacetic acid reacted with different sulfoxonium ylides, the corresponding products exhibited fluorescence, and furthermore, several products displayed antiproliferative activities against various human cancer cell lines.

Cooperative Triple Catalysis Enables Deaminative α-Indolmethylation of Carbonyl Compounds with Gramines

α-Functionalization of carbonyl compounds is an important reaction in synthetic chemistry. However, the development of novel synthetic strategies to realize this reaction is challenging. This study describes the α-indolmethylation of carbonyl compounds using cooperative copper, amine, and hydrogen-bond catalysis. This reaction provides a novel and efficient strategy for developing indolmethylated carbonyl compounds by deaminative coupling of gramines.

Transition-Metal-Free Base-Promoted Deaminative Coupling of Gramines with Aminomaleimides

The direct utilization of amines for C-C bond formation without prefunctionalization remains a significant challenge. Herein, we report the base-promoted deaminative coupling of gramines with aminomalaimides under redox-neutral conditions. In this operationally simple reaction, a series of indolmethyl-substituted aminomaleimides that emitted fluorescence were synthesized in good-to-excellent yields. Biological evaluation revealed that some products exhibited antiproliferative activity against human cancer cell lines.

Copper-Catalyzed Asymmetric Cyanation of Propargylic Radicals via Direct Decarboxylation of Propargylic Carboxylic Acids

Chiral propargylic cyanides are often used as small-molecule feedstocks for the introduction of chiral centers into various valuable products and complex molecules. Here, we have developed a highly atom-economical strategy for the chiral copper complex-catalyzed synthesis of chiral propargylic cyanides. Propargylic radicals can be smoothly obtained by direct decarboxylation of the propargylic carboxylic acids without preactivation. The reactions show excellent selectivity and functional group compatibility. Gram-scale reaction and several conversion reactions from chiral propargylic cyanide have demonstrated the synthetic value of this strategy.

Copper-Mediated Cyclization of o-Hydroxyaryl Enaminones with 3-Indoleacetic Acids toward the Synthesis of 3-Indolmethyl-Chromones

Here, we describe a copper-mediated tandem decarboxylative coupling/annulation protocol of o-hydroxyaryl enaminones with 3-indoleacetic acids. A series of 3-indolmethyl-chromones were afforded in up to 97% yield. A one-pot method for 3-indolmethyl-chromones from o-hydroxy acetophenones, N, N-dimethylformamide dimethyl acetal, and 3-indoleacetic acids was also developed. Derivatization of the products was conducted to provide various indolmethyl-substituted pyrimidines. Moreover, a biological evaluation revealed that some compounds had anti-influenza viral activities.

Copper-Mediated Decarboxylative Coupling of 3-Indoleacetic Acids with Pyrazolones

A copper-mediated decarboxylative coupling reaction of 3-indoleacetic acids with pyrazolones was described. This protocol realized new functionalization of pyrazolones under simple reaction conditions and exhibited high functional group compatibility and broad substrate scope. Notably, the products displayed antiproliferative activity against cancer cells.

Decarboxylative Amination of Benzoic Acids Bearing Electron-Donating Substituents and Non-Activated Amines

Efficient methods for decarboxylative activation of benzoic acids into great valuable products are highly sought after. Here we report a highly desirable and straightforward decarboxylative amination of readily available benzoic...