4-Bromoaniline → 1-Methylethyl{(3S)-3-[(4-bromophenyl)amino]butanoyl}carbamate

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Reaction Steps

Similarly a second batch of 1-methylethyl (2E)-2-butenoylcarbamate (Intermediate 49, 8.51 g, 49.7 mmol) was stirred in Toluene (255 ml) under nitrogen and (R-BINAP)ditriflatebis(acetonitrile)palladium(II) (3.04 g, 2.73 mmol) added. The catalyst formed a gummy ball, the solution turned to an opaque yellow mixture and was stirred for 20 mins. 4-bromoaniline (12.83 g, 74.6 mmol) was added, the solution turned a clear light brown and the gummy catalyst dissolved further. The mixture was stirred overnight. The two reaction mixtures were combined and loaded on to a 1.5 kg Isco silica Redisep column. The column was eluted with DCM:MeOH (0%−>0.5%, 19 CV). The clean, product containing fractions were evaporated to a pale brown oil. The mixture was dried in a vacuum oven overnight at 40° C. to give a white solid (24.2 g, 67% overall).

Provenance & Evidence