Decarboxylative 1,3-dipolar cycloadditions of l-proline.

1,3-Dipolar cycloaddition is one of the important chemical reactions between a 1,3-dipole and a dipolarophile to construct a five-membered heterocyclic compound. As an available α-amino acid reactant, l-proline is extensively used in 1,3-dipolar cycloaddition reactions. A diverse spectrum of bioactive spiro and fused N-heterocycles is obtained through this synthetic approach. In this review, we have described the use of l-proline in the synthesis of various spiro- and fused heterocyclic scaffolds.