[CH3:1][CH:2]1[CH2:7][CH2:6][C:5]([CH3:9])([CH3:8])[CH2:4][C:3]1=O.[CH2:11]([NH2:18])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].C(O)(=O)C>C1(C)C=CC=CC=1.C(Cl)Cl.O>[CH2:11]([NH:18][CH:3]1[CH2:4][C:5]([CH3:9])([CH3:8])[CH2:6][CH2:7][CH:2]1[CH3:1])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1
A mixture of crude racemic 2,5,5-trimethyl-cyclohexanone (theoretically 31.7 mmol) and benzylamine (3.8 mL, 34.79 mmol) in 50 mL of toluene was stirred for 45 minutes at reflux with continuous removal of H2O. The reaction mixture was cooled to RT and evaporated. The residue was taken into 50 mL of DCM and sodium triacetoxyborohydride (8.1 g, 38.22 mmol) was added, followed by acetic acid (2 mL, 34.94 mmol). The resulting mixture was stirred at RT overnight before being diluted with DCM and washed with saturated aqueous NaHCO3. The aqueous layer was back extracted twice with DCM. The combined organic layers were dried (Na2SO4), filtered, and evaporated. The residue was purified (DCM/(DCM:MeOH:NH4OH 60:10:1] 90% DCM) to give 3.84 g of racemic benzyl-(2,5,5-trimethyl-cyclohexyl)-amine. NMR showed the presence of about 5% of the trans isomer.
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