Tetrahydrofuran → 2-(3-Hydroxy-1,1-dimethyl-3-trifluoromethylhex-5-ynyl)benzoic acid

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Reaction Steps

To a solution of 5,5-dimethyl-3-prop-2-ynyl-3-trifluoromethyl-1,3,4,5-tetrahydrobenzo[c]oxepin-1-ol (2.50 g, 8.38 mmol) in tert-BuOH (75 mL) was added a 2.0 M solution of 2-methyl-2-butene in THF (58 mL, 117 mmol). To this solution was added a solution of sodium chlorite (4.74 g, 42.0 mmol) and sodium hydrogen phosphate (11.57 g, 84.0 mmol) in water (37.5 mL). The reaction mixture was stirred for 6 hours then the volatiles were removed in vacuo. The aqueous mixture was then acidified to pH=1 with aqueous 1M HCl, extracted with 300 mL of ethyl acetate, dried with magnesium sulfate, filtered, and concentrated in vacuo. The crude was purified by flash chromatography (120 g SiO2, hexanes to 1:1 hexanes:EtOAc) to give 2-(3-hydroxy-1,1-dimethyl-3-trifluoromethylhex-5-ynyl)benzoic acid (2.30 g, 87%). MS (ES+) m/z 315 [M+H]+.

Provenance & Evidence