Synthesis of 7-azabicyclo[2.2.1]heptanes by anionic cyclization

Article abstract of DOI:10.1016/S0040-4039(99)00018-0

Cyclizations of α-amino-organolithiums, derived by tin-lithium exchange, which proceed via a stereoselective two-electron process and totally regiospecific 5-exo-trig ring closure, have been extended to the preparation of the 7-azabicyclo[2.2.1]heptane ring system. Cyclization occurs from either the cis or the trans isomer of 5-allyl-2-tri-n-butylstannyl-N- benzylpyrrolidine to give only the exo product as a single diastereomer in isolated yields up to 83%.