In organic chemistry, a 1,3-dipolar compound or 1,3-dipole is a dipolar compound with delocalized electrons and a separation of charge over three atoms. They are reactants in 1,3-dipolar cycloadditions.
The dipole has at least one resonance structure with positive and negative charges having a 1,3 relationship which can generally be denoted as , where a may be a carbon, oxygen or nitrogen, b may be nitrogen or oxygen, and c may be a carbon, oxygen or nitrogen.
Known 1,3-dipoles are:
* Azides ()
* Ozone ()
* Nitro compounds ()
* Diazo compounds ()
* Some oxides
** Azoxide compounds (RN(O)NR)
** Carbonyl oxides (Criegee zwitterions)
** Nitrile oxides ()
** Nitrous oxide ()
** Nitrones ()
* Some imines:
** Azomethine imine
** Nitrilimines (, analogous to nitrile oxide)
** Carbonyl imines
* Some ylides
** Azomethine ylide
** Nitrile ylide ()
** Carbonyl ylide
** Thiosulfines ()