Benzyl chloroformate → (S)-1-((Benzyloxy)carbonyl)-4-(tert-butoxycarbonyl)piperazine-2-carboxylic acid

Participants

Reaction Steps

To a stirred suspension of (S)-4-(tert-butoxycarbonyl) piperazine-2-carboxylic acid (1.0 g, 4.34 mmol) in water (5 mL) was added solid NaHCO3 (0.73 g, 8.68 mmol) at room temperature. The reaction mixture was stirred at room temperature to get clear solution. Solution of CBZ-Cl (1.22 mL, 8.68 mmol) in 1,4-dioxane (10 mL) was added dropwise and the reaction mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with water (20 mL) and extracted with EtOAc (2×20 mL). The aqueous layer was acidified with 0.5M aqueous HCl to pH 5 and extracted with EtOAc (2×50 mL). The combined organic layers were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to afford the title compound (1.30 g) as white solid.

Provenance & Evidence