Sulfuric Acid → tert-butyl (2S)-2-amino-3-phenylpropanoate

Participants

Reaction Steps

98% H2SO4 (7 mL; 0.13 mol) was dripped over 20 min into dioxane (70 mL), maintaining the temperature of the solution below 20° C. After addition of L-phenylalanine (commercial product) (16.5 g; 0.10 mol), the solution was stirred over 12 h at 132 kPa under an isobutene (commercial product) atmosphere (consumed isobutene 45 g; 0.80 mol). The solution was dropped into a mixture of ice (200 g) and 10 N NaOH (30 mL, 0.30 mol) and extracted with Et2O (1 L). After washing with H2O (150 mL), the organic phase was dried over Na2SO4 and evaporated in vacuo. The residue was distilled to give L-phenylalanine 1,1-dimethylethyl ester (13 g; 0.059 mol). Yield 59%.

Provenance & Evidence