Aziridines from bromo-amines

Reduction of iV-(3-bromopropyl) imines gives a bromo-amine in situ, which cyclizes to the aziridine. Five-membered ring amines (pyrrolidines) can be prepared from alkenyl amines via treatment with N-chlorosuccinimide (NCS) and then BusSnH. " Internal addition of amine to allylic acetates, catalyzed by Pd(PPh3)4, leads to cyclic products via a Sn2 reaction. Acyclic amines can be prepared by a closely related reaction using palladium catalysts. Three-membered cyclic amines (aziridines)... 

Reduction of A -(3-bromopropyl) imines gives a bromo-amine in situ, which cyclizes to the aziridine. Five-membered ring amines (pyrrolidines) can be prepared from alkenyl amines via treatment with A -chlorosuccinimide and then... 

Of course, aziridines can also be synthesized by the ring-closing reactions of appropriately substituted amines. For example, halohydrins of type 142 are converted to iV-hydroxy-aziridines 144 by treatment with hydroxylamine derivatives, followed by base-catalyzed intramolecular Sn2 reaction of the intermediate p-haloaminoesters 143 under phase-transfer conditions <03TL3259>. A -Bromoethylimines 146, formed from the reaction of benzaldehyde derivatives (e.g., 145) and 2-bromo-2-methylpropylamine hydrobromide, undergo nucleophilic attack by methoxide, followed by intramolecular displacement of bromide to form A -(a-methoxybenzyl)aziridines 147 <03TL1137>. 

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