From top to bottom, azides, nitrones, and nitro compounds are examples of 1,3-dipoles.
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, as follows: 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.
They are reactants in 1,3-dipolar cycloadditions.IUPAC Gold Book dipolar compounds
Known 1,3-dipoles are: Azides () Ozone () Nitro compounds () Diazo compounds () Some oxides Azoxide compounds (RN(O)NR) Carbonyl oxides (Criegee zwitterions)https://www.organic-chemistry.org/namedreactions/ozonolysis-criegee-mechanism.shtm Ozonolysis mechanism on Organic Chemistry Portal siteLi, Jie Jack: Criegee mechanism of ozonolysis Book: Name Reactions. 2006, 173-174, 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 ()
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