The preparation of (S)-3-methylamino-3-[(R)-pyrrolidin-3-yl]propanenitrile (1), a key fragment of fluoroquinolone antibiotic PF-00951966 and others was achieved by N-methylative aziridine ring opening, addition of methyl group at the ring nitrogen, and ring-opening via a cyanide nucleophile in a single operation starting from bicyclic (R)-2-[(R)-pyrrolidine-3-yl]aziridine. The starting compound was elaborated from stereoselective conjugate addition of nitromethane to (R)-aziridine-2-yl acrylate followed by selective reduction without breaking the aziridine ring.

中文翻译：

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N-甲基化氮丙啶开环与（S）-3-甲基氨基-3-[（R）-吡咯烷-3-基]丙烷腈的合成

N-甲基化氮丙啶开环可以制备（S）-3-甲基氨基-3-[（R）-吡咯烷-3-基]丙烷腈（1），氟喹诺酮类抗生素PF-00951966的关键片段。从双环（R）-2-[（R）-吡咯烷-3-基]氮丙啶开始的单个操作中，在环氮上加成甲基，并通过氰化物亲核试剂开环。通过将硝基甲烷立体选择性共轭加成至（R）-氮丙啶-2-基丙烯酸酯，然后在不破坏氮丙啶环的情况下进行选择性还原，来制备起始化合物。