反应详情

A solution of 4-cyanobenzyl bromide (625 mg, 3.27 mmol) in dry THF (4 mL) was added slowly over ~3 min. to a suspension of activated Zn (dust; 250 mg) in dry THF (2 mL) at 0° under an argon atmosphere. The ice-bath was removed and the slurry was stirred at room temperature for a further 30 min. Then 3-bromopyridin-4-carboxylic acid methyl ester (540 mg. 2.5 mmol) followed by dichlorobis(triphenylphosphine)nickel (II) (50 mg). The resultant reddish-brown mixture was stirred for 3 h at ~40°-45° C. The mixture was cooled and distributed between EtOAc (100 ml,) and 5% aqueous citric acid (50 mL). The organic layer was washed with H2O(2×50 mL), dried with Na2SO4. After evaporation of the solvent the residue was purified on silica gel, eluting with 35% EtOAc in hexane to give 420 mg as a clear gum. FAB ms (M+1)253.

1. customThe ice-bath was removed
2. stirringThe resultant reddish-brown mixture was stirred for 3 h at ~40°-45° C
3. temperatureThe mixture was cooled
4. washThe organic layer was washed with H2O(2×50 mL)
5. dry with materialdried with Na2SO4
6. customAfter evaporation of the solvent the residue
7. customwas purified on silica gel
8. washeluting with 35% EtOAc in hexane
9. customto give 420 mg as a clear gum