A mixture of 1-ethynyl-4-phenoxy-benzene (126 mg, 0.65 mmol) and (S)-3-(4-azido-phenyl)-2-tert-butoxycarbonylamino-propionic acid (200 mg, 0.65 mg) in H2O:dioxane (5:1) was heated at 100° C. in a sealed tube for overnight. After completion of reaction, 3N HCl (5 ml) was added and the mixture was stirred for 2 hr at 50° C. Removal of solvent gave crude product which was dissolved in MeOH and purified by preparative HPLC to give 45 mg of desired product (yield: 29%). 1H-NMR (400 MHz, CD3OD): δ (ppm) 3.2 (m, 1H), 3.4 (m, 1H), 4.3 (m, 1H), 6.9 (d, 2H), 7.0 (d, 2H), 7.2 (m, 1H), 7.3 (d, 2H), 7.4-7.55 (m, 6H), 8.0 (s, 1H).
