A Mild Multi-Component Reaction for the Synthesis of 4,5-Disubstituted 1 H -1,2,3-Triazoles from Phosphonium Salts, Aldehydes, and Sodium Azide

A mild and metal-free multi-component reaction to synthesize 4,5-disubstituted 1 H -1,2,3-triazoles from phosphonium salts, aldehydes, and sodium azide is described. The process undergoes an organocatalyzed coupling of formyl group with phosphonium to form a key intermediate, olefinic phosphonium salt, which is followed by the [3+2] cycloaddition of the azide to the activated alkene. A series of representative 4,5-disubstituted 1 H -1,2,3-triazoles were prepared.