Synthesis of N-substituted phthalimides via Pd-catalyzed [4+1] cycloaddition reaction.

A novel Pd-catalyzed assembly of N-substituted phthalimides by merging of [4+1] cycloaddition and difluorocarbene transfer carbonylation from 2-iodo-N-phenylbenzamides and difluorocarbene precursors is disclosed. Difluorocarbene acts as a carbonyl source and simultaneously forms one C-C bond, one C-N bond and one CO bond to produce N-substituted phthalimides in high yields.

TsCl-promoted thiolation of quinoline N-oxides with thiophenols.

A metal-free method for the regioselective synthesis of 2-thiolated quinolines from quinoline N-oxides in water at room temperature is developed. The reaction is conducted using benzenethiols as thiolation reagents in the presence of p-toluenesulfonyl chloride via p-toluenesulfonyl chloride-assisted tandem C-H bond activation, nucleophilic addition, deoxygenation and aromatization processes. This method does not require the use of metal catalysts and oxidants. It shows the advantages of wide functional group tolerance, short reaction times and simple operation.

Synthesis of 10H-indolo[1,2-a]indol-10-ones via palladium-catalyzed C-H bond activation and difluorocarbene transfer.

A Pd-catalyzed annulation between 1-(2-iodophenyl)-1H-indoles and sodium difluorochloroacetate has been developed to synthesize 10H-indolo[1,2-a]indol-10-one derivatives via C-H bond activation and difluorocarbene transfer. Our route enables facile access to the targeted products with various substituents in moderate to high yields. This method features high reactivity, good functional group tolerance, a simple operation procedure, and mild reaction conditions. The reaction can be carried out on a gram scale.

An Olefin-based, Fluorescent Covalent Organic Framework for Selective Sensing of Aromatic Amines.

Owing to various chemical structures and different basicity of amines, a fluorescent probe that could distinguish aromatic and aliphatic amines is highly desirable for practical applications. Herein, an olefin-based, fluorescent COF (COF-Py-AN) with unique π-electron deficient groups was synthesized, which was a functionalized platform to realize sensing of π electron-rich aromatic amines. COF-Py-AN displayed fluorescence quenching in the presence of aromatic amines like aniline, with excellent selectivity against a variety of aromatic molecules, and the detection limit of COF-Py-AN toward aniline was as low as 1.29 µM. More importantly, COF-Py-AN could realize discriminating between aromatic and aliphatic amines. Furthermore, density functional theory calculations showed that the photoinduced electron transfer mechanism contributes to fluorescence sensing. This is the first example of olefin-based fluorescent COF materials for selective sensing of aromatic amines.