Optically active prolinols can be converted into optically active 3-fluoropiperidines by treatment with DAST. The reaction often produces 2-fluoromethylpyrrolidines as byproducts. The ring expansion was also applied to 2-hydroxypiperidines to produce 3-fluoroazepanes. The rearrangement proceeds via an aziridinium intermediate. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
光学活性脯
氨醇可以通过
DAST 处理转化为光学活性
3-氟哌啶。该反应通常会产生 2-
氟甲基
吡咯烷作为副产物。扩环也适用于
2-羟基哌啶以产生 3-
氟氮杂
环庚烷。重排通过
氮丙啶中间体进行。(© Wiley-
VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)