Alicyclic‐Amine‐Derived Imine‐BF3 Complexes: Easy‐to‐Make Building Blocks for the Synthesis of Valuable α‐Functionalized Azacycles

Abstract A new strategy to access α‐functionalized alicyclic amines via their corresponding imine‐BF 3 complexes is reported. Isolable imine‐BF 3 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‐BF 3 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.