Borane;tetrahydrofuran → Ethyl 3-(1-(aminomethyl)cyclopentyl)-5-(hydroxymethyl)benzoate

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-(ethoxycarbonyl)-5-(1-cyanocyclopentyl)benzoic acid (0.4 g, 1.4 mmol) in 14 mL THF, cooled to 0° C., was added borane-tetrahydrofuran complex (1M in THF, 5.6 mL, 5.6 mmol) dropwise. The reaction was stirred at 0° C. for 1.5 h and then at rt for 3.5 h. The mixture was quenched with MeOH, concentrated, diluted with EtOAc and washed with water and brine. Drying and solvent evaporation gave ethyl 3-(1-(aminomethyl)cyclopentyl)-5-(hydroxymethyl)benzoate and ethyl 3-(1-cyanocyclopentyl)-5-(hydroxymethyl)benzoate. The crude mixture was dissolved in 6.6 mL CH2Cl2, cooled to 0° C. and treated with carbon tetrabromide (0.56 g, 1.7 mmol). A solution of triphenylphosphine (0.42 g, 1.6 mmol) in 6.6 mL CH2Cl2 was added and the reaction was stirred at 0° C. for 1 h. Concentration and flash chromatography (silica gel, 0-20% EtOAc/hexanes) gave ethyl 3-(bromomethyl)-5-(1-cyanocyclopentyl)benzoate. 1H NMR (400 MHz, CDCl3) δ 8.02 (t, J=1.9 Hz, 2H), 7.70 (t, J=1.7 Hz, 1H), 4.52 (s, 2H), 4.41 (q, J=7.1 Hz, 2H), 2.53 (m, 2H), 2.12-1.97 (m, 6H), 1.41 (t, J=7.1 Hz, 3H).

Provenance & Evidence