Diaziridines slow nitrogen inversion

Diaziridines also show slow nitrogen inversion, and carbon-substituted compounds can be resolved into enantiomers, which typically racemize slowly at room temperature (when Af-substituted with alkyl and/or hydrogen). For example, l-methyl-3-benzyl-3-methyl-diaziridine in tetrachloroethylene showed a half-life at 70 °C of 431 min (69AG(E)212). Preparative resolution has been done both by classical methods, using chiral partners in salts (77DOK(232)108l), and by chromatography on triacetyl cellulose (Section 5.08.2.3.1). 

Since the separation of the cyclic 7-chloro-7-azabicyclo[4,l,0]heptane (45) into its isomers there has been much interest in slow inversion at nitrogen in heterocyclic compounds. Slow inversion in a diaziridine (43) has already been mentioned. A -Methoxyaziridines, e.g. (46), also invert slowly,as do oxazetidines (47), the isoxazolidine (48), and the oxazolidine (49). Solvent effects on inversion rates were investigated for the compound (48). Z-Ray experiments have confirmed the existence of two isomers of the compound (49). Further examples of studies of intramolecular processes in oxygen-nitrogen ring compounds include those of the three-membered ring series (50). ... 

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