One-Pot Suzuki-Hydrogenolysis Protocol for the Modular Synthesis of 2,5-Diaryltetrazoles

Al(OTf)3-Catalyzed Regioselective N2-Arylation of Tetrazoles with Diazo Compounds

Regioselective methods to access alkylated tetrazoles still remain a challenging goal. Herein, we describe a novel regioselective protocol for N2-arylation of tetrazoles with diazo compounds using inexpensive Al(OTf)3. This reaction could be conducted under mild conditions to access a diverse array of alkylated tetrazoles with 2-substituted tetrazoles as the major products, demonstrating a comprehensive range of substrate compatibility and excellent functional group compatibility. Mechanistic studies revealed a carbene-free process in this reaction procedure. Furthermore, the scale-up reaction and transformations of the N2-arylation of tetrazole products demonstrated the potential of this strategy.

Metal-Free Regioselective N2-Arylation of 1H-Tetrazoles with Diaryliodonium Salts

We describe a simple, metal-free regioselective N²-arylation strategy for 5-substituted-1H-tetrazoles with diaryliodonium salts to access 2-aryl-5-substituted-tetrazoles. Diaryliodonium salts with a wide range of both electron-rich and previously challenged electron-deficient aryl groups are applicable in this method. Diversely functionalized tetrazoles are tolerable also. We have devised a one-pot system to synthesize 2,5-diaryl-tetrazoles directly from nitriles. The synthetic utility of this method is furthered extended to late-stage arylation of two biologically active molecules.

Understanding the regioselectivity of 5-substituted 1H-tetrazoles alkylation

A novel rational to account for the selectivity of 5-substituted 1H-tetrazole alkylation.

Alkylation of 5-Substituted 1H-Tetrazoles via the Diazotization of Aliphatic Amines

A new alkylation reaction of monosubstituted tetrazoles via the diazotization of aliphatic amines is reported. This method enables preferential formation of 2,5-disubstituted tetrazoles. A one-pot 1,3-dipolar cycloaddition/diazotization sequence starting from widely available nitriles is also described. Azide residues are quenched in the second step with the nitrite reagent, thus limiting the intrinsic risk associated with trimethylsilyl azide. The reaction conditions were compatible with several functional groups, including thiocyanates, which afford preferentially disubstituted 2-alkyl-5-(substituted-thio)tetrazoles.

Light-Triggered Click Chemistry

The merging of click chemistry with discrete photochemical processes has led to the creation of a new class of click reactions, collectively known as photoclick chemistry. These light-triggered click reactions allow the synthesis of diverse organic structures in a rapid and precise manner under mild conditions. Because light offers unparalleled spatiotemporal control over the generation of the reactive intermediates, photoclick chemistry has become an indispensable tool for a wide range of spatially addressable applications including surface functionalization, polymer conjugation and cross-linking, and biomolecular labeling in the native cellular environment. Over the past decade, a growing number of photoclick reactions have been developed, especially those based on the 1,3-dipolar cycloadditions and Diels-Alder reactions owing to their excellent reaction kinetics, selectivity, and biocompatibility. This review summarizes the recent advances in the development of photoclick reactions and their applications in chemical biology and materials science. A particular emphasis is placed on the historical contexts and mechanistic insights into each of the selected reactions. The in-depth discussion presented here should stimulate further development of the field, including the design of new photoactivation modalities, the continuous expansion of λ-orthogonal tandem photoclick chemistry, and the innovative use of these unique tools in bioconjugation and nanomaterial synthesis.