To a solution of the crude (2R)-4-(4-cyano-1H-pyrazol-1-yl)-2-methyl-2-(methylsulfonyl)butanoic acid in 2-methyltetrahydrofuran (20 mL) was added N-methyl morpholine (0.494 g, 4.83 mmol, 3 eq) and CDMT (0.424 g, 2.42 mmol, 1.5 eq). The solution was allowed to stir at room temperature for one hour. O-tetrahydro-2H-pyran-2-yl-hydroxylamine (0.283 g, 2.42 mmol, 1.5 eq) was added to the solution, and the reaction mixture was allowed to stir for an additional hour at room temperature. Water (20 mL) was added, and the solution was extracted with 2-methyltetrahydrofuran (100 mL). The aqueous layer was re-extracted with 2-methyltetrahydrofuran (150 mL) and the combined organic layers were washed with brine. The organic layer was dried over sodium sulfate, filtered, and concentrated. The crude product mixture was purified by flash chromatography on a 40 g silica column eluting with 70-100% EtOAc/Heptane to give (2R)-4-(4-cyano-1H-pyrazol-1-yl)-2-methyl-2-(methylsulfonyl)-N-(tetrahydro-2H-pyran-2-yloxy)butanamide (165 mg, 28% yield over two steps) as a white solid. LC-MS M−H 369.4.
