Azodicarboxylic dipiperidide (0.31 g, 1.23 mmol) is stirred in 5 mL toluene at −30 to −20 deg C. Tri-n-butyl phosphine (0.31 mL, 1.23 mmol) is added dropwise and the mixture is stirred at −30 to −20 deg C. 10–15 min. An intimate mixture of (3-hydroxy-phenyl)-acetic acid methyl ester (0.13 g, 0.77 mmol) and 2-[4-isopropyl-2-(4-trifluoromethyl-phenyl)-oxazol-5-yl]-propan-1-ol (0.20 g, 0.701 mmol) in toluene (5 mL) is added dropwise and the resulting mixture is stirred 18 hr at room temperature. The thick suspension is diluted with 25 mL ether and cooled on ice/water for 30 min. The mixture is filtered, concentrated, and purified via silica gel chromatography eluting with 98:2 hexanes:acetone to afford the title compound as a colorless thick oil, 0.10 g, 31%. MS M++1 462. The structure is confirmed by 1H NMR spectroscopy.
