What is a Click Reaction?

Of all the advances that have transformed modern science over the past few decades, click chemistry is one of the most exciting. Fast, efficient and user-friendly, the framework is utilised across a wide range of industries, from pharmaceutical research to materials sciences. Reactions are the bread and butter of click chemistry and are ultimately what allow scientists to synthesise molecules and create complex chemical structures, from scratch.

In an article published in the journal Pharmaceutical Research, the authors describe click chemistry as a “group of reactions that are fast, simple to use, easy to purify, versatile, regiospecific, and give high product yields.”

The art of ‘snapping’ molecules together

So, what exactly is a click reaction? Read on to find out more about click chemistry and the reactions that allow scientists to ‘snap’ molecules together.

Chemists K. Barry Sharpless, Morten Meldal and Carolyn Bertozzi were recently awarded the Nobel Prize in Chemistry for their work on click reactions and bioorthoganal chemistry. Professor Olof Ramström, who sits on the Nobel Committee and helps select winners explains how the method allows scientists to “connect molecules in essentially the same way you build Legos.”

Simple, reliable and fuss-free

The roots of click chemistry can be traced back to 2000 when American chemist K. Barry Sharpless coined the term. In a press release published on the Nobel Prize website, click chemistry is described as “a form of simple and reliable chemistry, where reactions occur quickly and unwanted by-products are avoided.”

The idea was to create a minimalist, fuss-free method for synthesising complex molecules. The process is powered by a small but highly effective group of reactions. The Nobel committee draws comparisons with IKEA flatpack furniture (the molecular building blocks of click chemistry) which can be assembled using simple tools like screwdrivers and Allen keys (click chemistry reactions).

Shortly after introducing the world to the concept of click chemistry, he and fellow chemist Morten Meldal discovered the copper catalysed azide-alkyne cycloaddition (CuAAC). They used this copper catalyst to trigger chemical reactions between alkynes and azides. This presented exciting new opportunities for molecular synthesis, including in the stem cell research field.

Defining a ‘click’ reaction

To be considered click reactions, reactions must have the following characteristics:

• Modular and compatible with many different molecular building blocks
• Efficient and high yielding, with minimal by-products
• Simple and easy to purify, without creating toxic waste
• No complicated reactions conditions required
• Easy to acquire starting materials and basic compounds
• Readily available solvents such as water
• Fast rection times

Want to know more about click chemistry? Don’t miss our complete guide to the Nobel-awarded framework in ‘What is Click Chemistry? Everything You Need to Know’.