Triethylamine → methyl (2S,3R,5E)-3-({[(1S)-2,2-dimethyl-1-({[(1R)-1-phenylethyl]amino}carbonyl)propyl]amino}carbonyl)-2-ethoxy-6-(3-fluoro-4-phenoxyphenyl)hex-5-enoate

Participants

Reaction Steps

A mixture of palladium acetate (12 mg, 0.05 mmol) and tri-(2-methylphenyl)phosphine (30 mg, 0.10 mmol) in anhydrous acetonitrile (1 mL) was sonicated at room temperature for 1 min until a creamy-coloured suspension formed. This suspension was added via Pasteur pipette to a stirred solution of methyl (2S,3R)-3-({[(1S)-2,2-dimethyl-1-({[(1R)-1-phenylethyl]amino}carbonyl)propyl]amino}carbonyl)-2-ethoxy-hex-5-enoate (415 mg, 0.96 mmol), 3-fluoro-4-phenoxy-bromobenzene (Preparation 10)(400 mg, 1.50 mmol), and triethylamine (280 μL, 2.0 mmol) in anhydrous acetonitrile (1 mL) under nitrogen. The mixture was purged with nitrogen, then heated at reflux for 16 h. After being cooled, the mixture was poured into ethyl acetate (70 mL) and washed with 5% aqueous citric acid (20 mL), saturated aqueous sodium chloride (50 mL), dried (MgSO4), and concentrated under reduced pressure. The residue was purified by flash chromatography (gradient elution with dichloromethane:ethyl acetate) to give mainly methyl (2S,3R,5E)-3-({[(1S)-2,2-dimethyl-1-({[(1R)-1-phenylethyl]amino}carbonyl)propyl]amino}carbonyl)-2-ethoxy-6-(3-fluoro-4-phenoxyphenyl)hex-5-enoate as a pale yellow foam (359 mg, 69%). 1H nmr suggested that two alkene isomers, the (5Z) and (4E) were also present. The mixture of alkenes was taken onto the next step (see c, below).

Provenance & Evidence