6-Arylphenanthridines from Aryl o -Biaryl Ketones with 1,1,1,3,3,3-Hexamethyldisilazane and Molecular Iodine

Chiral TPE Foldamers in Macrocycles: Aggregation Enhanced Emission and Circularly Polarized Luminescence

Chiral macrocycles with circularly polarized luminescence (CPL) have attracted increasing attention due to the rigid structure, symmetrical chiral geometry and large luminescence dissymmetry factors (glum ). However, most chiral macrocycles are more emissive in solutions but have weakened fluorescence quantum yields (ΦF ) in aggregates, limiting their further application. In this paper, chiral macrocycle R/S-PhTPE was synthesized by combining chiral macrocycle architectonics with Z-o-phenyltetraphenylethylene (PhTPE) foldamer. Enhanced solution state emission and characteristic aggregation enhanced emission (AEE) effect can be observed for R/S-PhTPE due to the folded PhTPE conformation. Macrocycle immobilization and folded conformation endow PhTPE moiety with stable helical conformation. Most importantly, R/S-PhTPE exhibits opposite CPL signals compared with common chiral TPEs, demonstrating the evident impact of folded conformation. This work reports the first and deep insights into the chiroptical properties of chiral PhTPE foldamers, and will provide a new strategy to tune ΦF and CPL signals of AIE active chiral macrocycles.

Synthesis of Six-Membered N-Heterocycle Frameworks Based on Intramolecular Metal-Free N-Centered Radical Chemistry

The formation of intramolecular C-N bond represents a powerful strategy in organic transformation as the great importance of N-heterocycles in the fields of natural products and bioactive molecules. This personal account describes the synthesis of cyclic phosphinamidation, benzosultam, benzosulfoximine, phenanthridine and their halogenated compounds through transition-metal-free intramolecular oxidative C-N bond formation. Mechanism study reveals that N-X bond is initially formed under the effect of hypervalent halogen, which is very unstable and easily undergoes thermal or light homolytic cleavage to generate nitrogen radical. Then the nitrogen radical is trapped by the arene to give aryl radical. Rearomatization of aryl radical under the oxidant to provide corresponding N-heterocycle. Under suitable conditions, the N-heterocycles can be further transformed to halogenated N-heterocycles.

Recent progress in application of nanocatalysts for carbonylative Suzuki cross-coupling reactions

In the past few decades, cross-coupling of aryl halides and arylboronic acids in the presence of carbon monoxide (CO), also called carbonylative Suzuki coupling, to form two new carbon-carbon bonds in the production of synthetically and biologically important biaryl ketones, has been widely studied. Consequently, various catalytic systems have been extensively investigated in order to maximize the efficiency of this appealing area of biaryl ketone synthesis. As evidenced in the literature, nanometal-based systems are among the most powerful catalysts for this transformation as their large surface area to volume ratio and reactive morphologies allow faster reaction rates under milder CO pressure even at very low catalyst loadings. This review aims to provide an overview of the recent advances and achievements in the application of nano-sized metal catalysts for carbonylative Suzuki cross-coupling reactions, which may serve as an inspiration to researchers in their future work.

Preparation of 4-arylquinazolines with o-(N-alkyl,N-p-tosyl)aminobenzonitriles, aryllithiums, and NIS

The treatment of o-(N-alkyl,N-p-tosyl)aminobenzonitriles with aryllithiums, followed by the reaction with water, NIS under irradiation with a fluorescent lamp, and then ^tBuOK gave 2-alkyl-4-arylquinazolines or 4-arylquinazolines in good to moderate yields. The present reaction proceeds through the formation of N-iodoimines from imines with NIS, the generation of iminyl radicals, the 1,6-H shift by iminyl radicals, the cyclization via 6-exo-tet mode, and finally the elimination of p-toluenesulfinate to generate 2-alkyl-4-arylquinazolines or 4-arylquinazolines.