Asymmetric Synthesis of Aziridines by Reduction of N-tert-Butanesulfinyl -Chloro Imines

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• 作者：Bram Denolf ; Erika Leemans ; Norbert De Kimpe
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：April 27, 2007
• 年：2007
• 卷：72
• 期：9
• 页码：3211 - 3217
• 全文大小：163K
• 年卷期：v.72,no.9(April 27, 2007)
• ISSN：1520-6904

文摘

Reduction of (R_S)-N-tert-butanesulfinyl -halo imines afforded chiral aziridines in good to excellentyields. Upon reduction of (R_S)-N-tert-butanesulfinyl -halo imines with NaBH₄ in THF, in the presenceof 10 equiv of MeOH, (R_S,S)--halo sulfinamides were formed in excellent yield (up to 98%) with verygood stereoselectivity (>98:2). Simple treatment of the latter (R_S,S)--halo-tert-butanesulfinamides withKOH afforded the corresponding (R_S,S)-N-(tert-butylsulfinyl)aziridines in quantitative yields. On thecontrary, its epimer, (R_S,R)-N-(tert-butylsulfinyl)aziridine was synthesized by switchover of the reducingagent from NaBH₄ to LiBHEt₃. (R_S,R)-N-(tert-Butylsulfinyl)aziridines were synthesized in good yields(up to 85%) and diastereoselectivity (up to 92:8) by reduction of (R_S)-N-tert-butanesulfinyl -halo imineswith LiBHEt₃ in dry THF and subsequent treatment with KOH. All chiral aziridines were obtained as asingle diastereomer after recrystallization (overall yield up to 91%) or after flash chromatography.