[C:1]1([CH:7]([OH:19])[CH2:8][C:9](=[O:18])[CH2:10][C:11]([O:13][C:14]([CH3:17])([CH3:16])[CH3:15])=[O:12])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C([BH3-])#N.[Na+]>CC(C)[O-].CC(C)[O-].CC(C)[O-].[Cl-].[Ti+4]>[C:1]1([CH:7]([OH:19])[CH2:8][CH:9]([OH:18])[CH2:10][C:11]([O:13][C:14]([CH3:15])([CH3:17])[CH3:16])=[O:12])[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1By carrying out the reaction as in Example 9 but starting from 1.06 g of t-butyl 5-phenyl-5-hydroxy-3-oxopentanoate and using 1.05 cm3 of titanium chloride triisopropoxide (4.17 mmol) and 281.4 mg of sodium cyanoborohydride (4.24 mmol), there is obtained, after reacting for 3 hours 30 minutes, with a yield of 68%, 720 mg of t-butyl 5-phenyl-3,5-dihydroxypentanoate for which the syn/anti ratio is equal to 95/5.
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