Palladium‐Catalyzed Cascade Carbonylative Cyclization Reaction of Trifluoroacetimidoyl Chlorides and 2‐Iodoanilines: Toward 2‐(Trifluoromethyl)quinazolin‐4(3H)‐ones Synthesis

Recent advances in the synthesis of trifluoromethyl-containing heterocyclic compounds via trifluoromethyl building blocks

Trifluoromethylated heterocyclic compounds have played an increasingly significant role in pharmaceuticals, agrochemicals, and materials. This is because the introduction of trifluoromethyl could enhance the lipophilicity, metabolic stability, and pharmacokinetic properties of heterocyclic drug molecules. Therefore, the synthesis of trifluoromethylated heterocyclics has become a major subject of research. The construction of trifluoromethylated heterocyclics via the annulation of trifluoromethyl building blocks with suitable partners has been proved to be a powerful strategy. In this review, we systematically summarize and discuss recent advances in the preparation of trifluoromethyl-containing heterocyclics via trifluoromethyl building block strategies over the period from 2019 to the present.

Metal-free synthesis of 3-trifluoromethyl-1,2,4-triazoles via multi-component reaction of trifluoroacetimidoyl chlorides, hydrazine hydrate and benzene-1,3,5-triyl triformate

A convenient approach for the construction of pharmaceutically valuable 3-trifluoromethyl-1,2,4-triazoles has been developed, which employs the readily available trifluoroacetimidoyl chlorides, hydrazine hydrate and benzene-1,3,5-triyl triformate (TFBen) as starting materials. The multi-component reaction features broad substrate scope, high efficiency, and scalability, providing a facile and straightforward route to the biologically important 3-trifluoromethyl-1,2,4-triazole scaffolds in moderate to good yields. Considering its broad-spectrum pharmaceutical activity, the method offers the opportunity for the further study towards the toxicity risk assessment and structure-activity relationship of the pharmaceuticals containing trifluoromethyl-1,2,4-triazole cores.

TFBen (Benzene-1,3,5-triyl triformate): A Powerful and Versatile CO Surrogate

Carbonylative reactions by the using of CO surrogates constitute a facile avenue for the assembly of valuable carbonyl-containing compounds due to the colorless, toxic, flammable, and not easy-handing character of carbon monoxide gas. Recent advances in the carbonylative transformations with TFBen (benzene-1,3,5-triyl triformate) as a safe and convenient CO precursor are systematically summarized and discussed, which can be divided into three parts based on the patterns of the obtained products. This Review focuses on the discussion of the application of TFBen in carbonylative synthesis of various carbonyl-containing compounds.

Silver-Mediated [3 + 2] Cycloaddition of Azomethine Ylides with Trifluoroacetimidoyl Chlorides for the Synthesis of 5-(Trifluoromethyl)imidazoles

A silver-mediated [3 + 2] cycloaddition of azomethine ylides with trifluoroacetimidoyl chlorides for the rapid assembly of 5-(trifluoromethyl)imidazoles has been developed. Notable features of the reaction include readily accessible reagents, a broad substrate scope, and high efficiency. The protocol can be successfully applied to construct the analogue of the specific allosteric modulator of GABA_A receptors. The silver species could be recycled by a simple operation.

Palladium-catalyzed carbonylative synthesis of 5-trifluoromethyl-1,2,4-triazoles from trifluoroacetimidohydrazides and aryl iodides

A new palladium-catalyzed three-component carbonylative procedure for the construction of 5-trifluoromethyl-1,2,4-triazoles from trifluoroacetimidohydrazides and aryl iodides has been developed. TFBen is applied as a safe and convenient solid CO surrogate here.

Switchable and efficient conversion of 2-amido-aryl oxazolines to quinazolin-4(3H)-ones and N-(2-chloroethyl)benzamides

Switchable chemoselective conversion of 2-amido-aryl oxazolines to quinazolin-4(3H)-ones or N-(2-chloroethyl)benzamides is achieved.