*3.1. Reduction of (1S,4R,E)-1-[(Dimethylamino)methyl]-7,7-dimethylbicyclo[2.2.1]heptan-2-one oxime*

Oxime (7.6 mmol, 1.6 g) was dissolved in propan-1-ol (86 mL) and heated to 95 °C. Then, small pieces of sodium (approximately 50 mg) were added continuously for 1 h at 95 °C; care was taken to ensure that the unreacted sodium (excess sodium) remained present in the reaction mixture at all times during the reaction. After completion of the reaction, the volatiles were evaporated in vacuo. The residue was dissolved in a mixture of water (20 mL) and Et2O (80 mL). The organic phase was washed with water (2 × 20 mL) and NaCl (aq. sat., 1 × 20 mL), dried over anhydrous Na2SO4, and the volatiles were evaporated in vacuo. Diastereomers **1a** and **2a** were formed in a ratio of 2.6:1. The diastereomers were separated by column chromatography (Silica gel 60, EtOAc/MeOH/Et3N = 4:1:1).
