To a solution of 2,6-dimethylphenol (184 mg, 1.51 mmol), triphenylphosphine (396 mg, 1.51 mmol), and methyl 3-(hydroxymethyl)-5-(1-methylethyl)-4-isoxazolecarboxylate (300 mg, 1.51 mmol) in toluene (4 mL) was slowly added diisopropyl azodicarboxylate (0.272 mL, 1.51 mmol). The solution was heated in a microwave reactor at 90° C. for 10 minutes and then allowed to stand at ambient temperature overnight. The solution was concentrated and purified by chromatography (silica gel, 2.5% acetone in hexanes) to afford methyl 3-{[(2,6-dimethylphenyl)oxy]methyl}-5-(1-methylethyl)-4-isoxazolecarboxylate (329 mg, 72%). 1H-NMR (400 MHz, DMSO-d6) δ 7.02-6.90 (m, 3H), 5.00 (s, 2H), 3.74 (s, 3H), 3.72 (septet, J=7 Hz, 1H), 2.17 (s, 6H), 1.28 (d, J=7 Hz, 6H).
