Dimethyl Sulfoxide → (S)-4-(tert-butoxycarbonyl)-1-(3-chlorophenyl)-5-[2-(oxo)ethyl]piperazin-2-one

Participants

Reaction Steps

To a solution of oxalyl chloride (0.608 mL, 6.97 mmol) in dichloromethane (40 mL) at -78° C. was added DMSO (0.990 mL, 13.9 mmol) over 2-3 minutes. The solution was stirred for 10 minutes, then a solution of the alcohol from Step E of Example 43 (2.06 g, 5.81 mmol) in 10 mL of dichloromethane was added over 5 minutes, keeping the reaction temperature below -70° C. The reaction was stirred for 10 minutes, then triethylamine (2.43 mL) was added, and the reaction was stirred at -78° C. for 5 minutes, then allowed to warm to room temperature. After 45 minutes, the solution was poured into dichloromethane, and washed with sat. NH4Cl soln., 10% citric acid soln., water, and brine. The solution was dried (Na2SO4), filtered, and concentrated in vacuo to provide the titled aldehyde.

Provenance & Evidence