Kai Yang

An efficient DBDMH-initiated bifunctionalization of quinoxalin-2(1 H )-ones has been achieved. The synthetic applicability is further demonstrated by gram-scale synthesis and versatile product derivatizations.

A novel metal-free ortho-C–H borylation of 2,5-bis(phenylselanyl)pyridines using BBr3 has been developed. This method affords diverse bis(selenium)boronates with excellent site-selectivity in moderate to excellent yields. Furthermore, the downstream transformation of the resulting boronates provides a convenient route to access functionalized organoseleniums. Given the importance of organoseleniums and the limited availability of existing methods for synthesizing organoselenium boronates, the protocol holds significant value in both synthetic chemistry and medicinal chemistry.

A synthetic protocol for the construction of 3,4-disubstituted cinnoline scaffolds was described, which allowed for the transformation of ortho-alkynyl arylhydrazides via iron-catalyzed cascade C–H functionalization/cycloaddition. Furthermore, the practical utility of this method had been validated by easily scale-up synthesis, substrates derived from bioactive molecules and versatile derivatization of the target products. Mechanistic studies revealed that the reaction possibly proceeds via twice iron-mediated single-electron transfer (SET) processes. Furthermore, the resulting 3,4-disubstituted cinnolines exhibited significant anti-inflammatory effects from LPS stimulation experiment.

Herein, a facile and efficient strategy for one-pot synthesis of 3-aminoalkyl chromones from o-hydroxyaryl enaminones and aromatic amines using inexpensive rongalite as a C1 source has been developed. This three-component protocol enables domino aminomethylation and annulation of o-hydroxyphenyl enaminones without the need for transition metals or oxidants, featuring simple operation, a broad substrate scope, and readily available raw materials, providing a series of 3-aminomethyl chromones in moderate-to-good yields.

The imidazo[1,2-a]pyridine skeleton is widely present in many natural products and pharmaceutical agents. Due to its impressive and significant biological activities, such as analgesic, anti-tumor, antiosteoporosis, and anxiolytic properties, the derivatization of imidazo[1,2-a]pyridine skeleton has attracted widespread attention from chemists. In recent years, significant progress has been made in the derivatization of imidazo[1,2-a]pyridines through direct C-H functionalization, especially through visible light induction. This review highlights recent advances in visible light-induced C-H functionalization of imidazo[1,2-a]pyridines during the past ten years, and some reaction mechanisms are also discussed.

Oxazoles are important five-membered heterocycles that contain both nitrogen and oxygen atoms. Due to their wide range of biological activities, many oxazoles demonstrate potential for extensive application in various fields, including medicinal chemistry. Trifluoromethyl carbinol, an important pharmacophore, contains both trifluoromethyl and hydroxyl groups and is common in molecules with important biological activities. Constructing oxazoles that contain a trifluoromethyl carbinol unit is undoubtedly important and valuable for expanding the chemical space in drug discovery. In this study, a simple and efficient method was developed for the synthesis of oxazoles containing a CF₃-substituted alcohol unit via the tandem cycloisomerization/hydroxyalkylation of N-propargylamides with trifluoropyruvates through a rational Lewis acid catalytic mechanism. This Zn(OTf)₂-catalyzed synthetic protocol is operationally simple and provides a series of oxazoles in moderate to good yields. The protocol demonstrates broad substrate scope, high functional group tolerance, and high atom economy and can achieve gram-level reactions, indicating the strong possibility of its practical application.

As an important class of nitrogen-containing fused heterocyclic compounds, imidazo[1,2-a]pyridines often exhibit significant biological activities, such as analgesic, anticancer, antiosteoporosis, anxiolytic, etc. Using Y(OTf)₃ as a Lewis acid catalyst, a simple and efficient method has been developed for the synthesis of C₃-alkylated imidazo[1,2-a]pyridines through the three-component aza-Friedel–Crafts reaction of imidazo[1,2-a]pyridines, aldehydes, and amines in the normal air atmosphere without the protection of inert gas and special requirements for anhydrous and anaerobic conditions. A series of imidazo[1,2-a]pyridine derivatives were obtained with moderate to good yields, and their structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS. Furthermore, this conversion has the advantages of simple operation, excellent functional group tolerance, high atomic economy, broad substrate scope, and can achieve gram-level reactions. Notably, this methodology may be conveniently applied to the further design and rapid synthesis of potential biologically active imidazo[1,2-a]pyridines with multifunctional groups.