Absolute Configuration of 2‐Substituted 2‐Azabicyclo[2.2.1]hept‐5‐enes

Abstract

Abstract The diastereoisomeric 2‐substituted 2‐azabicyclo[2.2.1]hept‐5‐enes 2 – 4 were prepared by aza‐ Diels ‐ Alder reaction of cyclopentadiene with the corresponding methaniminium ions. Their relative configurations were deduced using 1 H, 1 H‐ROESY experiments, and their absolute configurations were assigned from the crystal structure of the aziridinium derivative (−)‐ 5 . The absolute configuration of (+)‐ 1 , i.e . (1 R ), was assigned by CD spectroscopy.