3-benzoyl-4-methyl-2-phenyl-1,3-oxazolidin-5-one

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Into a solution of hexamethyldisilazane (17.5 g, 106 mmol) in THF (100 mL) was added n-butyllithium (1.58 M in hexane, 50 mL, 78.5 mmol) at −78° C. After 5 min at −78° C., the solution was allowed to warm to 0° C. for 30 min and then cooled to −78° C. again. A solution of 3-benzoyl-4-methyl-2-phenyl-1,3-oxazolidin-5-one (dried overnight in vacuo before using, 20 g, 71 mmol) in THF (250 mL) was added slowly under argon, and the dark red brown solution was stirred at this temperature for 3 h. A solution of N-(bromomethyl)phthalimide (22.2 g, 92.5 mmol) in THF (200 mL) was then added dropwise. The reaction mixture was allowed to warm to 20° C. in 4 h and stirred at this temperature overnight. The solvent was evaporated. The residue was dissolved in 10% NH4Cl (250 mL) and extracted with CH2Cl2. The organic phase was dried over Na2SO4 and evaporated. Recrystallization from CH2Cl2 and ether (1:4) gave white crystals of 2-((3-benzoyl-4-methyl-5-oxo-2-phenyloxazolidin-4-yl)methyl)isoindoline-1,3-dione (23 g, 74%). LC-MS (ES, m/z): 441 [M+H]+. cooled to −78° C. again to warm to 20° C. in 4 h stirred at this temperature overnight The solvent was evaporated The residue was dissolved in 10% NH4Cl (250 mL) extracted with CH2Cl2 The organic phase was dried over Na2SO4 evaporated Recrystallization from CH2Cl2 and ether (1:4)