Bromide ion → rel-(1R,3S)-3-Benzoylcyclohexanecarboxylic acid

Beteiligte Stoffe

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Reaktionsschritte

A stirred solution of 1,3-cyclohexanedicarboxylic anhydride (67 mg, 0.43 mmol) (prepared from 1,3-cyclohexanedicarboxylic acid as described in patent application US 2004010005) and copper(I) iodide (8 mg, 0.04 mmol) in dry THF (3 mL) was cooled to −70° C. and phenmagnesium bromide in THF (0.4 mL of 1 M, 0.40 mmol) was added dropwise over 2 min. The mixture was stirred at −70° C. for 1 h and allowed to warm slowly to rt. After 2 h the mixture was poured into ether (75 mL) and extracted with satd aqueous NaHCO3 (2×30 mL). The combined aqueous extracts were acidified to pH 1 by cautious addition of concentrated HCl and back extracted with ether (2×50 mL). These ether extracts were combined, dried over Na2SO4 and evaporated under reduced pressure to afford cis-3-benzoylcyclohexane-1-carboxylic acid (78 mg, 77%) as an oil which solidified on standing. 1H NMR (CDCl3) δ 1.3-2.8 (9H), 3.32 (m, 1H), 7.45 (m, 2H), 7.55 (1=m, 1H), 7.92 (m, 2H). MS ESI+ve m/z 233 (M+1).

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