Ring Enlargement of Polyhydroxylated Pyrrolidines to Piperidines by Mitsunobu Reaction: A Fortuitous Synthesis of 1-Deoxy-<scp>l</scp>-allonojirimycin
作者:Alessandro Dondoni、Alberto Marra、Barbara Richichi、Daniela Perrone
DOI:10.1055/s-2004-829566
日期:——
corresponding R-protected pyrrolidines and 2-deoxy-piperidines in different ratios depending on the stereochemistry of the starting pyrrolidine and the nature of the acid R-OH. A mechanistic scheme is proposed involving the formation of an aziridinium ion as an intermediate. A piperidine derivative obtained in 74% yield was converted in four steps into the title allonojirimycin.
手性 3,4-二苄氧基-5-羟甲基-2-噻唑基吡咯烷在光延条件下(R-OH、Ph 3 P、DIAD in THF,80 °C)得到不同比例的相应 R-保护的吡咯烷和 2-脱氧-哌啶取决于起始吡咯烷的立体化学和酸 R-OH 的性质。提出了涉及形成氮丙啶鎓离子作为中间体的机制方案。以 74% 产率获得的哌啶衍生物分四步转化为标题别异野尻霉素。