Ethyl Acetate → (S)-4-(tert-butoxycarbonyl)-5-(carboxymethyl)-1-(3-chlorophenyl)piperazin-2-one

Participants

Reaction Steps

To a solution of the aldehyde from Step A (1.52 g, 4.31 mmol) in 2-methyl-2-propanol (50 mL) and 2-methyl-2-butene (10 mL) at room temperature was added a solution of sodium chlorite (585 mg, 5.17 mmol) and sodium dihydrogenphosphate (595 mg, 4.31 mmol) in 10 mL of water. The reaction turned yellow, then slowly faded to light pink over 45 minutes. The solution was poured into EtOAc, and washed with sat. sodium bisulfite soln. The aqueous layer was acidified to pH 3 with 2.75M KHSO4 soln., and extracted several times with EtOAc. The combined organic extracts were dried (Na2SO4), filtered, and concentrated in vacuo to provide the titled carboxylic acid.

Provenance & Evidence