C1(P(CC)C2C=CC=CC=2)C=CC=CC=1.[CH3:16][C:17]1([CH3:24])[C:21]([CH3:23])([CH3:22])[O:20][BH:19][O:18]1.[C:25]([NH:28][C:29]([CH:41]1[CH2:44][C:43]([CH2:48][C:49]2[CH:54]=[CH:53][C:52]([Cl:55])=[CH:51][CH:50]=2)([NH:45][CH:46]=[O:47])[CH2:42]1)([CH2:37][CH2:38][CH:39]=[CH2:40])[C:30]([NH:32][C:33]([CH3:36])([CH3:35])[CH3:34])=[O:31])(=[O:27])[CH3:26]>ClCCl>[C:25]([NH:28][C:29]([CH:41]1[CH2:42][C:43]([CH2:48][C:49]2[CH:54]=[CH:53][C:52]([Cl:55])=[CH:51][CH:50]=2)([NH:45][CH:46]=[O:47])[CH2:44]1)([CH2:37][CH2:38][CH2:39][CH2:40][B:19]1[O:20][C:21]([CH3:23])([CH3:22])[C:17]([CH3:24])([CH3:16])[O:18]1)[C:30]([NH:32][C:33]([CH3:36])([CH3:34])[CH3:35])=[O:31])(=[O:27])[CH3:26]While under argon, bis(1,5-dicyclooctadiene)diiridium(I)dichloride (15 mg, 0.022 mmol) and diphenylphosphinoethan (18 mg, 0.044 mmol) in dichloromethane (3 mL) was cooled to 0° C. and treated with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.430 mL, 2.95 mmol). After 30 min, a solution of 2-acetamido-N-tert-butyl-2-(3-(4-chlorobenzyl)-3-formamidocyclobutyl)hex-5-enamide (330 mg, 0.738 mmol) in dichloromethane (10 mL) was added and the cooling bath was removed. After 16 h, the solution was diluted with dichloromethane (20 mL) and washed with water and saturated aqueous sodium chloride. The organic layer was dried over MgSO4, filtered and concentrated to give the crude product (420 mg, 99%), which was used in the next step without further purification. ESI MS found for C30H47BClN3O5 m/z [576.8 (M+1), 574.7 (M−1)].
Loading…