p-Toluenesulfonic acid → (R)-3-phenyl-2-(5-phenyl-benzoxazol-2-ylmethoxycarbonylamino) Propionic Acid Allyl Ester

Participants

Reaction Steps

(5-Phenyl-benzoxazole-2-yl)methanol 51 (437 mg, 1.94 mmol) and carbonyldiimidazole (393 mg, 2.43 mmol) in 7 ml of dry CH2Cl2 were stirred at room temperature for 3 hrs. The tosic acid salt of (R)-phenylalanine allyl ester(767 mg, 1.94 mmol) was added followed by 0.42 ml of triethylamine (301 mg, 2.98 mmol). The mixture was stirred overnight. The mixture was diluted and washed with 1M HCl solution then with brine. After drying, the organic phase was filtered and concentrated. The crude product was chromatographed to give about 711 mg of (R)-3-phenyl-2-(5-phenyl-benzoxazol-2-ylmethoxycarbonylamino) propionic acid allyl ester 52.

Provenance & Evidence