text: Unlike most 1,3-dipolar cycloaddition reactions, in which the stereochemistry of the dipole is lost or non-existent, azomethine ylides are able to retain their stereochemistry. This is generally done by ring opening of an aziridine, and subsequent trapping by a dipolarophile before the stereochemistry can scramble.
  Like other 1,3-dipolar cycloaddition reactions, azomethine ylide cycloadditions can form endo or exo products. This selectivity can be tuned using metal catalysis.