To a round bottom flask was charged tert-butyl 4-hydroxy-3-methyl-1-oxo-2,8-diazaspiro[4.5]decane-8-carboxylate (1000 mg, 3.52 mmol), 4-bromofuran-2(5H)-one (860 mg, 5.28 mmol), Pd(OAc)2 (79 mg, 0.352 mmol), Xantphos (305 mg, 0.528 mmol), and K2CO3 (972 mg, 7.03 mmol). The flask was sealed, vacuumed and back filled with N2 and filled with dioxane (14 mL) and water (190 μL, 10.6 mmol). The reaction mixture was heated at 90° C. overnight, and filtered through CELITE®. The filtrate was evaporated to give the crude product, which was purified by column chromatography (0-10% MeOH/DCM, came out at 6% MeOH/DCM, followed by another column with 0-100% EtOAc/hex) to give the title compound. LC/MS: [(M+1)]+=367
