The Resolution and Absolute Configuration of 2,3-Methanopyroglutamic Acid, 3-Oxo-2-azabicyclo[3,1,0]hexane-1-carboxylic Acid

The resolution of racemic 2,3-methanopyroglutamic acid (∇Glp) was accomplished using L- and D-Leu-NH2 and both isomers were hydrolyzed to give optically active (Z)-2,3-methanoglutamic acids1) (∇ZGlu), respectively. The optical rotations of these samples were compared with ∇ZGlu obtained by hydrolysis of ∇Glp prepared by oxidation of (2S,3R)- or (2R,3S)-2,3-methanoproline1) (∇Pro), the absolute configurations of which were determined by X-ray diffraction earlier. These experiments showed (−)- and (+)-∇Glp to have the (2S,3S)- and (2R,3R)-configurations, respectively.