Kinetic resolution of N-acylaziridines by nucleophilic ring opening was achieved with (R)-BINOL as the chiral modifier under boron-catalyzed conditions (see scheme; Ar=3,5-dinitrophenyl). The consumed enantiomer of aziridine can be further converted to an enantioenriched 1,2-chloroamide with recovery of (R)-BINOL.

N-Acylaziridines are important starting materials for the synthesis of chiral amine derivatives. The traditional methods for producing these activated aziridines have significant drawbacks. The gram scale synthesis of N-acylaziridines by deprotection of N-tosylaziridines and reprotection with N-hydroxysuccinimide derivatives is described. Mono- and disubstituted aziridines perform well, with complete retention of stereochemical purity. The consistently moderate yields are linked to the N-tosylaziridine deprotection step, while acylation with N-hydroxysuccinimide derivatives is highly efficient.

Die kinetische Racematspaltung von N‐Acylaziridinen gelingt durch nucleophile Ringöffnung mit (R)‐BINOL als chiralem Modifikator unter Bor‐katalysierten Bedingungen (siehe Schema; Ar=3,5‐Dinitrophenyl). Das verbrauchte Enantiomer des Aziridins kann zu einem enantiomerenangereicherten 1,2‐Chloramid weiter umgesetzt werden, und (R)‐BINOL wird zurückgewonnen.

Functionalized tryptamines are targets of interest for development as small molecule therapeutics. The ring opening of aziridines with indoles is a powerful method for tryptamine synthesis where isomer formation can be controlled. 3,5-Dinitrobenzoyl (DNB)-protected aziridines undergo regioselective, enantiospecific ring opening to produce β-substituted tryptamines for a series of indoles. Attack at the more substituted aziridine carbon occurs in an S2-like fashion to generate DNB-tryptamine products as synthetic precursors.

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