A Novel Strategy for the Synthesis of 3-(<i>N</i>-Heteryl)pyrrole Derivatives

A flexible approach to unknown 1-(1H-pyrrol-3-yl)pyridinium salts with selective control of the substitution patterns, by the reaction of pyridinium ylides with 2H-azirines, is disclosed. 3-(Pyridinium-1-yl)pyrrolides, a new type of stable ylide, were prepared from these salts in high yields by treatment with base. Atmospheric-pressure hydrogenation of the ylides with Adams' catalyst lead to 1-(pyrrol-3-yl)piperidines in good yields.本研究公开了一种可实现取代模式选择性调控的柔性合成策略，用于制备未知的1-(1H-吡咯-3-基)吡啶鎓盐（1-(1H-pyrrol-3-yl)pyridinium salts），该策略通过吡啶鎓叶立德（pyridinium ylides）与2H-氮丙啶（2H-azirines）的反应构建。向此类盐中加入碱进行处理，可高收率得到一类新型稳定叶立德——3-(吡啶鎓-1-基)吡咯叶立德（3-(Pyridinium-1-yl)pyrrolides）。采用亚当斯催化剂(Adams' catalyst)对该类叶立德进行常压氢化，可获得高收率的1-(吡咯-3-基)哌啶。