4-Iodoanisole → 2-tert-Butoxycarbonylamino-5-(4-methoxy-phenyl)-pentanoic acid methyl ester

Participants

Reaction Steps

To a cooled (0° C.) mixture comprising 2-tert-butoxycarbonylamino-pent-4-enoic acid methyl ester (4.0 g, 17.46 mmol) in dry THF (60 mL) under an inert atmosphere of argon is added 9-BBN (70 mL of a 0.5 M solution in THF, 35.0 mmol). The reaction is stirred at RT for 2 h. To this mixture is added degassed DMF (50 mL) followed by an aqueous solution of potassium phosphate (12 mL of a 3 M aqueous solution, 36 mmol). 4-Iodoanisole (4.3 g, 18.8 mmol) is added immediately followed by PdCl2(dppf) (0.63 g, 0.86 mmol) and the mixture is stirred at RT overnight. The solvent is removed in vacuo and the crude residue is dissolved in EtOAc and filtered through Celite® (filter material). The filtrate is washed with saturated sodium hydrogen carbonate solution, water (×3), brine, and then dried (MgSO4) and concentrated in vacuo. Purification of the crude product by flash chromatography (SiO2, iso-hexane:EtOAc, 9:1) affords the title compound as a light brown oil.

Provenance & Evidence