Ring Expansion Induced by DAST: Synthesis of Substituted 3-Fluoropiperidines from Prolinols and 3-Fluoroazepanes from 2-Hydroxymethylpiperidines
作者:Ingrid Déchamps、Domingo Gomez Pardo、Janine Cossy
DOI:10.1002/ejoc.200700237
日期:2007.9
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)