Ethyldiphenylphosphine → N-(3-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)-1-(4-chlorophenyl)cyclobutyl)benzamide

Participants

Reaction Steps

While under argon, a solution of bis(1,5-dicyclooctadiene)diiridium(I)dichloride (58 mg, 0.086 mmol) and diphenylphosphinoethane (68 mg, 0.172 mmol) in dichloromethane (10 mL) was cooled to 0° C., and charged with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.66 mL, 11.44 mmol). After stirring for 15 min, a solution of N-(3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)-1-(4-chlorophenyl)cyclobutyl)benzamide (1.46 g, −2.8 mmol) in dichloromethane (35 mL) was added in one portion and the resulting solution was allowed to slowly warm to room temperature. After stirring for 16 h dichloromethane (40 mL) added and the organic layer was washed with water and saturated aqueous sodium chloride. The resulting solution was dried over MgSO4, filtered and concentrated to give the crude product as a mixture of diastereomers. Purification by flash column chromatography (20-80% ethyl acetate in heptane) gave two products. The more lipophilic isomer was isolated and used in the next step (590 mg, 0.924 mmol). 1H NMR (CDCl3, 600 MHz) δ 8.65 (s, 1H), 7.97 (s, 1H), 7.67 (d, J=7.2 Hz, 2H), 7.49-7.53 (m, 3H), 7.40-7.43 (m, 4H), 6.17 (s, 1H), 3.37-3.42 (m, 1H), 3.30-3.34 (m, 1H), 2.72-2.80 (m, 2H), 2.39-2.51 (m, 2H), 2.31 (s, 3), 1.66-1.72 (m, 2H), 1.30 (s, 9H), 1.19 (s, 12H), 1.10-1.17 (m, 2H), 0.83-8.89 (m, 1H), 0.72 (t, J=7.8 Hz, 2H). ESI MS found for C35H49BClN3O5 m/z [638.7/640.8 (M+1), 636.7/638.9 (M−1)]

Provenance & Evidence