Acetic Acid → 4,4,4-trifluoro-3-[(R)-2-(3-trifluoromethyl-phenyl)-morpholin-4-ylmethyl]-butyric acid ethyl ester

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Reaction Steps

A mixture of the unpurified racemic 4,4,4-trifluoro-3-formyl-butyric acid ethyl ester from above (step b), 0.498 g (2.15 mmol) of (R)-2-(3-trifluoromethyl-phenyl)-morpholine [prepared from (R)-2-(3-trifluoromethyl-phenyl)oxirane in a similar manner to that described in Example 4 (steps b-e)], 0.162 g (2.7 mmol) of acetic acid and 8 mL of dichloromethane was stirred at room temperature. After 30 min, 0.913 g (4.3 mmol) of sodium triacetoxyborohydride was added. The mixture was stirred overnight at room temperature and then diluted with ethyl acetate and washed successively with 0.5 M sodium carbonate solution, water and then brine. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by chromatography on silica gel, eluting with hexanes-ethyl acetate (90:10) to give 0.592 g (66%) of 4,4,4-trifluoro-3-[(R)-2-(3-trifluoromethyl-phenyl)-morpholin-4-ylmethyl]-butyric acid ethyl ester as an oil. Used as is in the next step

Provenance & Evidence