To a solution of 5.00 g of (4-hydroxy-phenyl)-carbamic acid tert-butyl ester, 7.28 g of 2-(5-methyl-2-phenyl-1,3-oxazol-4-yl)ethan-1-ol and 9.40 g of triphenylphosphine in 100 ml of THF was added at 0° C. a solution of 7.25 g of diisopropyl azodicarboxylate in 50 ml of THF over 30 min and stirring was continued at 22° C. for 16 h. A further portion of 1.88 g of triphenylphosphine and 1.45 g of diisopropyl azodicarboxylate in 10 ml of THF was added at 0° C. and stirring was continued at 22° C. for 2 h after which time conversion was complete. The mixture was evaporated and the residue purified by chromatography (SiO2, n-hexane/AcOEt 4:1) to give 7.5 g of the title compound as a colorless solid. MS: (M+H)− 395.4.
