反应详情

This ester (4 g, 0.022 mmol), copper (I) bromide-dimethyl sulfide complex (4.88 g, 0.023 mmol) in dimethyl sulfide (20 ml) and tetrahydrofuran (120 ml) was cooled to −40° C. under nitrogen and treated dropwise with 4-fluorophenylmagnesium bromide (1M solution in THF, 43.9 ml) so that the temperature did not rise above −40° C. Reaction was stirred for 20 minutes before quenching with 1N HCl (300 ml) and extracting the products with ether (3×300 ml). Combined organic phase washed with saturated sodium chloride, dried over magnesium sulfate and evaporated to dryness. The crude oil was purified by silica chromatography eluting with hexane-ethyl acetate mixtures (10-20%), to give ethyl [4-(4-fluorophenyl)-2-oxo-cyclohexyl]acetate as a colourless oil, 2.8 g. 1H NMR δ (ppm) (CDCl3): 7.26-7.11 (2H, m), 7.04-6.94 (2H, m), 4.18-4.11 (2H, m), 3.55-3.44 (1H, m), 3.00-2.90 (1H, m), 2.80-2.73 (2H, m), 2.69-2.55 (1H, m), 2.28-2.17 (2H, m), 2.10-1.88 (2H, m), 1.61-1.42 (1H, m) and 1.31-1.25 (3H, m).

1. customdid not rise above −40° C
2. customReaction
3. custombefore quenching with 1N HCl (300 ml)
4. extractionextracting the products with ether (3×300 ml)
5. washCombined organic phase washed with saturated sodium chloride
6. dry with materialdried over magnesium sulfate
7. customevaporated to dryness
8. customThe crude oil was purified by silica chromatography
9. washeluting with hexane-ethyl acetate mixtures (10-20%)