2-((R)-3-hydroxy-1,1-dimethyl-3-trifluoromethyl-6-trimethylsilanylhex-5-ynyl)benzamide → 2-((S)-3-hydroxy-1,1-dimethyl-3-trifluoromethylhex-5-ynyl)benzamide

To a stirred, ice-cooled, THF solution (100 mL) of 2-((R)-3-hydroxy-1,1-dimethyl-3-trifluoromethyl-6-trimethylsilanylhex-5-ynyl)benzamide (17.8 g, 46.2 mmol) n-tetrabutylammonium fluoride was added (51 mL of 1 M solution in THF, 51 mmol) dropwise via addition funnel. After 30 minutes, the reaction was quenched with 200 mL of 1 M HCl and further diluted with brine. The mixture was extracted with ethyl acetate. The combined extract was washed with water and brine, dried over anhydrous sodium sulfate, and the solvent removed in vacuo. The residue was redissolved in dichloromethane and the solvent evaporated. The residue was then dissolved in 30 mL of diethyl ether and triturated with hexanes. The precipitated solid was filtered. The filtrate was collected and the solvent evaporated, and the residue treated with diethyl ether/hexanes as before to obtain more solid precipitate. The solids were combined and dried in vacuo to give 2-((S)-3-hydroxy-1,1-dimethyl-3-trifluoromethylhex-5-ynyl)benzamide (10 g, 33% over two steps). This material was used without further purification.