[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([NH:9][C:10](=[O:15])[C:11]([CH3:14])([CH3:13])[CH3:12])=[C:5]([CH3:16])[CH:4]=1.[Li]CCCC.[CH2:22]1[O:25][C@@H:23]1[CH3:24]>C1COCC1>[OH:25][CH:23]([CH3:24])[CH2:22][CH2:16][C:5]1[CH:4]=[C:3]([O:2][CH3:1])[CH:8]=[CH:7][C:6]=1[NH:9][C:10](=[O:15])[C:11]([CH3:12])([CH3:13])[CH3:14]To a stirred solution of the the product from Step A (3.00 g, 13.6 mmol) at 0° C. in anhydrous THF (50 mL) was added a solution of 2.5 M n-BuLi in hexanes (13.6 mL, 2.5 equiv.) over about 2 min under a nitrogen atmosphere. After 10 minutes a solution of (R)-propylene oxide (1.18 g, 1.5 eq) in anhydrous THF (5 mL) was added and the mixture was stirred for about 30 min. The reaction was quenched by the addition of ice-water. The THF was evaporated and the residue was extracted with ethyl acetate to give a viscous oil (4.03 g), which was used in next reaction without further purification: LC/MS (+APCI) m/z 280 (M+H).
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