Benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate → (1R,3R,4S)-[4-((2S)-2-benzyloxycarbonylamino-4-methylsulfanyl-butyrylamino)-3-propyl-cyclohexyl]-carbamic acid tert-butyl ester

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Reaction Steps

A sample of (1R,3R,4S)-(4-amino-3-propyl-cyclohexyl)-carbamic acid tert-butyl ester (1.9 mmol) was dissolved in 1:1 CH2Cl2/DMF (40 mL), and the resultant solution was charged with N-Cbz methionine (591 mg, 2.1 mmol), N,N-diethylisopropylamine (1 mL, 5.7 mmol), and BOP (1.0 g, 2.3 mmol). The reaction was stirred for 12 h at RT and then partitioned between EtOAc and sat. NaHCO3; the aqueous phase was back extracted with EtOAc (1×). The organic phases were combined, washed with brine, dried (Na2SO4), filtered, and concentrated in vacuo. The residue was purified by flash chromatography to afford (1R,3R,4S)-[4-((2S)-2-benzyloxycarbonylamino-4-methylsulfanyl-butyrylamino)-3-propyl-cyclohexyl]-carbamic acid tert-butyl ester (375 mg). MS found: (M+H)+=522.3.

Provenance & Evidence