Development of boronic acid catalysts for direct amidation of aromatic carboxylic acids using fluorescence-based screening.

Direct amidation of carboxylic acids with amines holds significant importance; therefore, catalytic processes involving boronic acids have undergone extensive investigation. However, studies focused on the amidation of aromatic carboxylic acids remain limited. In this study, we introduce a fluorescence-based screening methodology employing an anthracene derivative probe, facilitating the rapid evaluation of various amidation catalysts.

Photocatalytic carbocarboxylation of styrenes with CO for the synthesis of γ-aminobutyric esters.

Metal-free photoredox-catalyzed carbocarboxylation of various styrenes with carbon dioxide (CO2) and amines to obtain γ-aminobutyric ester derivatives has been developed (up to 91% yield, 36 examples). The radical anion of (2,3,4,6)-3-benzyl-2,4,5,6-tetra(9H-carbazol-9-yl)benzonitrile (4CzBnBN) possessing a high reduction potential (-1.72 V vs.

Photoredox-Catalyzed α-Aminoalkylcarboxylation of Allenes with CO.

The photoredox-catalyzed α-aminoalkylcarboxylation of aryl allenes with CO and ,-dimethylanilines is reported for the first time (26 examples, up to 96% yield). In the case of electron-deficient allenes, good regioselectivity was observed (up to 94:6), exclusively generating kinetic products over thermodynamic products. This protocol is a novel synthetic method for highly functionalized β,γ-unsaturated γ-aminobutyric esters.

Ligand-free Suzuki-Miyaura cross-coupling with low Pd content: rapid development by a fluorescence-based high-throughput screening method.

Suzuki-Miyaura (SM) cross-coupling is one of the most effective strategies for carbon-carbon bond formation, but previous methods have several drawbacks, such as the requirement of complicated ligands, toxic organic solvents, and high-content-Pd catalysts. Thus, in this study, a highly efficient SM cross-coupling was developed using metal oxide catalysts: 0.02 mol% Pd, aqueous solvent, no ligand, and room temperature.

Transition-Metal-Free Borylation of Aryl Bromide Using a Simple Diboron Source.

In this study, we developed a simple transition-metal-free borylation reaction of aryl bromides. Bis-boronic acid (BBA), was used, and the borylation reaction was performed using a simple procedure at a mild temperature. Under mild conditions, aryl bromides were converted to arylboronic acids directly without any deprotection steps and purified by conversion to trifluoroborate salts.