1,3-Dipolar cycloaddition

What is 1,3-dipolar cycloaddition?

The 1,3-dipolar cycloaddition is a type of chemical reaction that utilizes 1,3-dipolar molecules, also known as 1,3-dipoles, and dipolarophiles, similar to how dienes and dienophiles are used in Diels-Alder cycloadditions. The pioneering work on this reaction was conducted by Huisgen in the 1960s, and subsequent studies were carried out by Huisgen, Padwa, Zecchi, and others.

1,3-Dipolar cycloaddition
Allyl type 1,3-dipolar cycloaddition

a, b, c = C, O, N

These 1,3-dipolar molecules are usually formed by the combination of carbon, nitrogen, and oxygen, and can be classified into two categories: the propargyl-allenyl type and the allyl type. The dipolarophiles can be either alkenes or alkynes. The end result of the reaction is a diverse array of five-membered heterocyclic molecules, which are frequently utilized in medicinal and pharmaceutical chemistry.

The use of the 1,3-dipolar cycloaddition is extensive in the formation of diverse five-membered heterocyclic molecules. This is achieved by combining various dipolar molecules, as previously mentioned, with either alkenes or alkynes.