[OH:1][C:2]1[CH:7]=[C:6]([CH3:8])[O:5][C:4](=[O:9])[C:3]=1[C:10](=[O:13])[CH2:11][CH3:12].[Li+].CC([N-]C(C)C)C.CN(P(N(C)C)(N(C)C)=O)C.Br[CH2:34][CH2:35][CH2:36][O:37][Si:38]([C:41]([CH3:44])([CH3:43])[CH3:42])([CH3:40])[CH3:39]>C1COCC1>[Si:38]([O:37][CH2:36][CH2:35][CH2:34][CH2:8][C:6]1[O:5][C:4](=[O:9])[C:3]([C:10](=[O:13])[CH2:11][CH3:12])=[C:2]([OH:1])[CH:7]=1)([C:41]([CH3:42])([CH3:43])[CH3:44])([CH3:40])[CH3:39]To 4-hydroxy-6-methyl-3-propionyl-2H-pyran-2-one (XII; 7 g, 38.5 mmol) in 60 ml anhydrous THF at −72° C. under argon, was added freshly prepared LDA (18.5 ml DIPEA in 150 ml THF with 52 ml 2.5 M n-butyllithium, Aldrich) in 150 ml anhydrous THF, and 20 ml HMPA (Aldrich). The reaction mixture was stirred for 1 h. 3-bromopropoxy-t-butyldimethylsilane (7 ml g; 27.7 mmol; Aldrich) in 50 ml anhydrous THF was added over 30 min, and stirred for an additional 5 min. The reaction mixture was quenched with saturated NH4Cl, extracted with 3×150 ml EtOAc, dried with brine and anhydrous Na2SO4, and evaporated to a yellowish oil. The product was purified via silica flash chromatography.
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