What Is Click Chemistry?

What Is Click Chemistry

Click chemistry is a concept introduced by Nobel laureate K. Barry Sharpless in 2001. It refers to a set of highly selective and reliable chemical reactions that can be used to construct complex molecular architectures. The term “click” signifies the ease and efficiency of these reactions, which proceed rapidly under mild conditions with high yields.

Click Chemistry Mechanism

The click chemistry reaction proceeds through the formation of an intermediate and the subsequent rearrangement to form a stable triazole product. This reaction is highly efficient, as it occurs under mild conditions (typically at room temperature) and proceeds rapidly with high yields, making it a valuable tool in chemical synthesis and other applications.

Click Chemistry Reactions

Copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC)

This is one of the most well-known click chemistry reactions. It involves the cycloaddition of an azide and a terminal alkyne catalyzed by copper(I) to form a 1,4-disubstituted 1,2,3-triazole. CuAAC is highly reliable, efficient, and works well in aqueous and non-aqueous solvents, making it popular for bioconjugation, polymer, and material science applications.

Strain-promoted azide-alkyne cycloaddition (SPAAC):

SPAAC eliminates the need for a metal catalyst by using a strained alkyne (such as cyclooctyne) that reacts with an azide at an enhanced rate due to the ring strain. This reaction is particularly useful in biological systems where the presence of a metal catalyst like copper could be detrimental.

Strain-promoted alkyne-nitrone cycloaddition (SPANC): 

This metal-free click reaction involves a strained alkyne and a nitrone. SPANC is particularly useful for applications that require metal-free conditions and can be utilized in the labeling of biomolecules and in material science.

Reactions of strained alkenes:

These reactions leverage the high reactivity of strained alkenes (such as norbornenes or trans-cyclooctenes) to undergo rapid and selective reactions, often without the need for catalysts. They find applications in bioorthogonal chemistry, where they are used to label biomolecules in living systems without interfering with native biochemical processes.

Alkene and azide [3+2] cycloaddition:

 This metal-free reaction allows for the cycloaddition of alkenes and azides to form pyrrolidines. While not as commonly used as azide-alkyne cycloadditions, this reaction type can offer unique selectivity and has potential applications in synthesizing nitrogen-containing heterocycles.

Alkene and tetrazine inverse-demand Diels-Alder:

This reaction exploits the inverse electron demand Diels-Alder reaction between a strained alkene and a tetrazine. It is highly selective, fast, and occurs under mild conditions, making it particularly attractive for use in live cell labeling and in vivo studies.

Alkene and tetrazole photoclick reaction: 

This is a light-mediated reaction where a strained alkene reacts with a tetrazole under UV irradiation. This type of reaction offers the advantage of spatial and temporal control, as the reaction only occurs upon irradiation with light, allowing for precise manipulation in biological and material science applications.


Click Chemistry Applications

Click chemistry has found applications in diverse fields, leveraging its simplicity, efficiency, and selectivity. Some notable applications include:

Drug Discovery and Development

Click chemistry plays a crucial role in drug discovery and development. It enables the synthesis of drug candidates with improved pharmacokinetic properties and bioavailability. Click reactions have been utilized in the creation of targeted drug delivery systems, drug-conjugates, and bioorthogonal chemistry for biological imaging.

Materials Science

Click chemistry has revolutionized materials science by enabling the synthesis of functional materials with tailored properties. It has been instrumental in the development of smart materials, self-healing polymers, and functionalized surfaces for applications in electronics, coatings, and biocompatible materials.


In bioconjugation, click chemistry offers an efficient method for linking biomolecules with diverse functionalities. By utilizing click reactions, researchers can attach fluorescent probes, drugs, and targeting ligands to biomolecules, facilitating studies on protein interactions, cellular processes, and diagnostics.

Polymer Synthesis

Click chemistry has significantly contributed to polymer synthesis. It allows the rapid and efficient construction of well-defined polymer architectures, such as dendrimers and block copolymers. Click reactions have enabled precise control over polymer structures, leading to advancements in drug delivery, nanotechnology, and materials engineering.

Surface Functionalization

Click chemistry provides a versatile toolbox for surface functionalization. By introducing click-compatible functional groups onto surfaces, researchers can tailor surface properties, create bioactive coatings, and develop sensors and biochips. Click chemistry has been utilized in the fabrication of microarrays, biosensors, and bioelectronics.

Click Chemistry Tools and Reagents

AxisPharm, provides a wide range of high quality click chemistry tools and reagents with very competitive pricing.

Our laboratories provide the highest level of technical support to our customers.