Ammonium Chloride → 8-(4-Fluorophenyl)-1,4-dioxaspiro[4.5]decan-8-ol

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Reaction Conditions

Reaction Steps

1,4-Cyclohexanedione mono-ethylene ketal (10.1 g, 64.7 mmol) was dissolved in anhydrous THF (100 mL), and the solution was cooled to −78° C. 4-Fluorophenylmagnesium bromide (78 mL of a 1.0 M solution in THF, 78 mmol) was added slowly over 10 minutes. After 20 minutes, saturated NH4Cl (10 mL) was added and the mixture allowed to warm to room temperature. The mixture was partitioned between CHCl3 and saturated NH4Cl. The organic layer was dried (Na2SO4), filtered through CELITE, and concentrated under reduced pressure. Purification by flash chromatography (silica gel, 1:9 to 3:7 EtOAc: hexanes, loaded in a minimum of CH2Cl2) gave 4-(4-fluoro-phenyl)-4-hydroxy-cyclohexanone ethylene ketal (10.9 g, 67%); 1H NMR (300 MHz, CDCl3) δ 7.5 (dd, J=8, 8 Hz, 2H), 7.05 (dd, J=8, 8 Hz, 2H), 4.00-3.91 (m, 5H), 2.25-2.08 (m, 4H), 1.85 (d, J=8 Hz, 2H), 1.65 (d, J=8 Hz, 2H).

Provenance & Evidence