5-Carboxy-2-azabicyclo[2.1.1]hexanes as Precursors of 5-Halo, Amino, Phenyl, and 2-Methoxycarbonylethyl Methanopyrrolidines

Novel 5-X-substituted-2-azabicyclo[2.1.1]hexanes (X = 5-<i>syn</i>-Cl, -Br, -I, -Ph, -NHCOOR (R = Me, Bn, <i>t</i>-Bu), -CH<sub>2</sub>CH<sub>2</sub>COOMe and X = 5-<i>anti</i>-Br, -I, -Ph) were synthesized from the X = 5-<i>syn</i>-carboxy derivative. New 5-<i>anti</i>-X-2-azabicyclo[2.1.1]hexanes, X = NHCOOR (R = Me, Bn), were prepared stereoselectively from the X = 5-<i>anti</i>-carboxy substrate.