4-Methylmorpholine → benzyl (S)-1-((1S,2R,4R)-4-(tert-butyldimethylsilyloxy)-2-propylcyclohexylamino)-4-(methylthio)-1-oxobutan-2-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

Examples 2t and 2u, Step 3: A solution of benzyl (1S,2S,4R)-4-(tert-butyldimethylsilyloxy)-2-((Z)-prop-1-enyl)cyclohexylcarbamate (0.3 g, 0.74 mmol) in 10 mL of 7:3 EtOH:EtOAc was charged with palladium hydroxide and stirred under hydrogen atmosphere for 22 h. The palladium was removed by filtration and the solution was charged with fresh palladium hydroxide before again being placed under hydrogen atmosphere (5 kg pressure). After 3 h, the mixture was filtered through celite with EtOAc washings and concentrated in vacuo. The residue was dissolved in DMF (3 mL) and the resultant solution was cooled to 0° C. before being charged successively with (S)-Cbz methionine (0.31 g, 1.1 mmol), N-methyl morpholine (0.24 mL, 2.2 mmol), and BOP reagent (0.48 g, 1.1 mmol). The reaction was slowly warmed to 30° C. and then stirred for 12 h before being quenched water. The mixture was extracted with EtOAc, and the combined organic phases were washed with brine, dried, filtered, and concentrated in vacuo. The residue was purified by flash chromatography to afford benzyl (S)-1-((1S,2R,4R)-4-(tert-butyldimethylsilyloxy)-2-propylcyclohexylamino)-4-(methylthio)-1-oxobutan-2-ylcarbamate (0.25 g). blah, blah. MS-found: (M+H)+=537.

Provenance & Evidence