Reactions at Carboxylic Acids and Their Derivatives

Aziridine-2-carboxylates can be converted to bicyclic boroxazolidones in one step with tri-ethylborane, as shown in Equation (11) in Section 1.01.6.2 92RTC2ii . These can be considered doubly protected a-amino acids, and can be converted back to the parent aziridine-2-carboxylates using a variety of conditions. 

Ester enolates on the side chain of aziridine have been used for intramolecular nucleophilic ringopening of the aziridine, as shown in Equation (20) in Section 1.01.6.3.1 93JOC5019 . 

Reactions at carboxyl groups in azirines are rare, perhaps due to competing reactivity at the C=N bond of the ring. 

The most common reactions of a vinyl or alkenyl group attached to a ring carbon atom are pericyclic processes involving the aziridine or azirine ring B-83MI 101-01 . These reactions were covered in Section 1.01.6. 

Diimide reduction of a side-chain alkene in an aziridine has been reported, which proceeds without destroying the aziridine ring 68JOC48l . 

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