[OH:1][N:2]1[C:6](=[O:7])[C:5]2=[CH:8][CH:9]=[CH:10][CH:11]=[C:4]2[C:3]1=[O:12].C([O-])(=O)C.[Na+].Cl[CH2:19][CH2:20][C:21]([CH3:27])([CH3:26])[C:22]([O:24][CH3:25])=[O:23].O>CS(C)=O.C(OCC)(=O)C>[CH3:26][C:21]([CH3:27])([CH2:20][CH2:19][O:1][N:2]1[C:3](=[O:12])[C:4]2=[CH:11][CH:10]=[CH:9][CH:8]=[C:5]2[C:6]1=[O:7])[C:22]([O:24][CH3:25])=[O:23]
To a stirred solution of 83.2 grams (0.51 mole) of N-hydroxyphthalimide in 500 ml of dimethyl sulfoxide was added 41.8 grams (0.51 mole) of sodium acetate. Upon completion of addition the reaction mixture was stirred for one hour at ambient temperature. After this time 84.2 grams (0.51 mole) of methyl 4-chloro-2,2-dimethylbutanoate was added dropwise. The reaction mixture was then heated to 100° C. where it stirred for 16 hours. The reaction mixture was cooled and 300 ml of water and 1000 ml of ethyl acetate were added. The mixture was shaken and the organic layer separated. The organic layer was washed with three 200 ml portions of water. The organic layer was dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residual oil. The oil was subjected to column chromatography on silica gel. Elution was accomplished with 1:3 ethyl acetate:heptane. The appropriate fractions were combined and concentrated under reduced pressure to a residual oil. The oil was dissolved in 500 ml of diethyl ether and washed with two 100 ml portions of aqueous 1N sodium hydroxide. The ether layer was concentrated under reduced pressure to give 90.3 grams of methyl 2,2-dimethyl-4-(phthalimidooxy)butanoate as an oil.
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