Synthesis of Enantiopure 2-Alkyl-1,3,3-Trinitroazetidines

Enantiopure 2-alkyl-1,3,3-trinitroazetidines 4 were efficiently synthesized by the nitrolysis of enantiopure 2-alkyl-3,3-dinitro-1-tosylazetidines 3 using an excess of fuming nitric acid in CHCl₃ at ambient temperature. In addition, elaboration of (S)-2-(2-methoxyethyl)-1,3,3-trinitroazetidine (4c) was successfully performed to synthesize a variety of enantiopure 2-alkyl-1,3,3-trinitroazetidines 5–7. The advantage of this strategy is that 2-alkyl-1,3,3-trinitroazetidines can be synthesized either asymmetrically or racemically depending on the presence or absence of chirality in N-sulfinyl aldimines 2 used as the starting material. Furthermore, the sensitivity measurement results of racemic 2-methyl-1,3,3-trinitroazetidine (racemic 4a) showed that the introduction of an alkyl substituent at the C2 position of 1,3,3-trinitroazetidine had a significant effect on the sensitivity of the resulting 2-alkyl-1,3,3-trinitroazetidine.