[NH2:1][C@@H:2]1[CH2:7][CH2:6][CH2:5][CH2:4][C@H:3]1[CH2:8][CH:9]([O:12][CH3:13])[O:10][CH3:11].C(OC(=O)COC)(C)C.COCC(N)=O>CC(OC)(C)C>[NH2:1][C@H:2]1[CH2:7][CH2:6][CH2:5][CH2:4][C@@H:3]1[CH2:8][CH:9]([O:10][CH3:11])[O:12][CH3:13]A dry solution of 2.1 g (11.2 mmole) trans-1-amino-2-(2,2-dimethoxyethyl)-cyclohexane and 1.38 g (10.4 mmole) methoxy acetic acid isopropyl ester in 20 ml MTBE was mixed with 200 mg immobilized lipase Novozym® 435 and shaken for 25 hours at room temperature. After this period of time the conversion was 49.5%. The (1R, 2S)-enantiomer was acylated to the methoxy acetamide, while the (1S, 2R)-enantiomer was not acylated. After removal of the enzyme by filtration, removal of the solvent using an rotary evaporator and purification by column chromatography (silica gel, eluation starting with MTSE and finally with MTBE/methanol)970 mg of pure (1S, 2R)-1-amino-2-(2,2-dimethoxyethyl)-cyclohexane (46% yield) were obtained.
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