engleski

ASYMMETRIC SYNTHESIS OF DISUBSTITUTED N-BOC, N-SES AND N-TS AZIRIDINES IN HIGH ENANTIOMERIC EXCESS ; DIASTEREOSELECTIVITY OF REACTIONS

Asymmetric synthesis of different N-tosyl-2, 3-disubstituted aziridines having high enantiomeric purity (98.7-99.9 %) has been recently reported [2]. In addition, and to further explore reaction diastereoselectivity, we have prepared a range of N-SES and N-Boc disubstituted aziridines, also in high enantiomeric excess (>98 %), starting from N-SES or N-Boc imines and benzyl-sulfonium salt 2 [3] derived from Eliel`s 1, 3-oxathiane 1. NaH was used to generate the ylide, as an alternative to more sensitive and expensive phosphazene base EtP2. We have also prepared a range of N-Ts disubstituted aziridines in THF as the solvent. Cis/trans ratios of prepared aziridines depended on the N-activating group, but also on the imine substituent, and varied from 100 % cis for 6d and 8d, to >98 % trans for 6e and 7a-c.

aziridines; asymmetric synthesis

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