What is click chemistry?

Click chemistry refers to a group of reactions that are fast, simple to use, easy to purify, versatile, regiospecific, and give high product yields.

With proper modification, click reactions can run at or near biological condition, produce stable products with little, non-toxic byproducts, and proceed quickly to high yield in one pot. It is now commonly used in bioconjugation to join substrates of choice with specific biomolecules. Examples of click reactions that are being used for bioconjugation are Staudinger ligation with azides, strain promoted Huisgen cycloaddition of azides, and tetrazine ligation.