Process for the preparation of 6,6-dimethyl-3-azabicyclo-[3.3.0]-hexane compounds and enantiomeric salts thereof

The present invention provides for a process for preparing racemic methyl 6,6-dimethyl-3-azabicyclo[3,1,0]hexane-2-carboxylate, its corresponding salt: (1R,2S,5S)-methyl 6,6-dimethyl-3-azabicyclo[3,1,0]hexane-2-carboxylate di-p-toluoyl-D-tartaric acid (“D-DTTA”) salt or a (1S,2R,5R)-methyl 6,6-dimethyl-3-azabicyclo[3,1,0]hexane-2-carboxylate di-p-toluoyl-L-tartaric acid salt (“L-DTTA”) in a high enantiomeric excess. This invention also provides for a process for preparing a (1R,2S,5S)-methyl 6,6-dimethyl-3-azabicyclo[3,1,0]hexane-2-carboxylate dibenzoyl-D-tartaric acid (“D-DBTA”) salt or a (1S,2R,5R)-methyl 6,6-dimethyl-3-azabicyclo[3,1,0]hexane-2-carboxylate L-tartaric acid (“L-DBTA”) salt in a high enantiomeric excess. Further, this invention provides a process for preparing intermediates II, IIB, III, IV, IV salt, V, VI, and VII.