AbstractA new strategy to access α‐functionalized alicyclic amines via their corresponding imine‐BF3 complexes is reported. Isolable imine‐BF3 complexes, readily prepared via dehydrohalogenation of N‐bromoamines in a base‐promoted/18‐crown‐6 catalyzed process followed by addition of boron trifluoride etherate, undergo reactions with a wide range of organometallic nucleophiles to afford α‐functionalized azacycles. Organozinc and organomagnesium nucleophiles add at ambient temperatures, obviating the need for cryogenic conditions. In situ preparation of imine‐BF3 complexes provides access to α‐functionalized morpholines and piperazines directly from their parent amines in a single operation. α‐Functionalized morpholines can be elaborated further, for instance by installing a second substituent in the α′‐position.
摘要 报告了一种通过相应的亚胺-BF3 复合物获得α-官能化脂环胺的新策略。可分离的亚胺-BF3 配合物在碱促进/18-冠-6 催化过程中通过 N-溴胺的脱氢卤化,然后加入三氟化硼醚化物而容易制备。有机锌和有机镁亲核物在常温下添加,无需低温条件。在原位制备亚胺-BF3 复合物的过程中,只需一次操作就能直接从母胺制备出 α-官能化吗啉和哌嗪。α-官能化吗啉还可以进一步制备,例如在 α′ 位上安装第二个取代基。