Borohydride → (R)-2-Amino-3-cyclohexylpropan-1-ol

The process is performed as in Example 1, starting with 6.2 g of ethyl (2R)-2-amino-3-cyclohexylpropionate and 1.93 g of sodium borohydride in 120 cm3 of absolute ethanol at about 5° C. for 10 minutes. The medium is warmed to room temperature and stirred for a further 3 h 30 minutes. After cooling again to about 5° C. and addition of a further 40.94 g of borohydride, followed by stirring at a temperature in the region of 20° C. for 65 hours, the reaction medium is concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C. A solid is obtained, which is purified by chromatography under a pressure of argon (100 kPa) on a column of silica gel (particle size 40-63μ; 320 g), eluting with pure methanol. The fractions containing the expected product are collected. These fractions are combined and then concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C. 5.16 g of (2R)-2-amino-3-cyclohexyl-1-propanol are obtained in the form of a sticky white solid. (Rf=0.25 in methanol on a Merck 60F254R silica plate).