[H-].[Na+].[OH:3][C:4]1([CH3:17])[CH2:9][CH2:8][N:7]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:6][CH2:5]1.[CH3:18]N(P(N(C)C)(N(C)C)=O)C.CI>C1COCC1>[CH3:18][O:3][C:4]1([CH3:17])[CH2:5][CH2:6][N:7]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:8][CH2:9]1A suspension of 60% NaH in mineral oil (160 mg, 4 mmol) in THF (5 mL) at room temperature was treated with a solution of Example 494A (430 mg, 2.00 mmol) in THF (5 mL), heated to 55° C. for 2 hours, cooled to room temperature, treated with HMPA (2.5 mL) and methyl iodide (0.50 mL), heated to 55° C. for 16 hours, cooled to room temperature, quenched with 10% aqueous citric acid, and extracted twice with diethyl ether. The combined extracts were washed sequentially with water, saturated NaHCO3, and brine, dried (MgSO4), filtered, and concentrated. The concentrate was purified by flash column chromatography on silica gel with 10%-20% ethyl acetate/heptane to provide the desired product.
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