Ammonium Chloride → rac-(S*)-5-(2,6-dimethoxyphenyl)-3-methylene-1-(4-(trifluoromethoxy)benzyl)pyrrolidin-2-one

Participants

Reaction Conditions

Reaction Steps

A cooled (−78° C.) mixture of methyltriphenylphosphonium bromide (754 mg; 2.11 mmol) in anh. THF (6 ml) was treated dropwise with a solution of n-BuLi (1.6 M in hexanes; 1.32 ml; 2.11 mmol). Stirring was then continued at rt, under nitrogen, for 30 min. The resulting mixture was then cooled to 0° C., and treated with a solution of 5-(2,6-dimethoxyphenyl)-1-(4-(trifluoromethoxy)-benzyl)pyrrolidine-2,3-dione (800 mg; 1.95 mmol) in anh. THF (4 ml). Stirring was continued at 0° C. for 25 min., and at 60° C. for 1 h. After cooling to rt, aq. sat. NH4Cl (25 ml) was added, and this mixture was extracted with AcOEt (3×50 ml). The mixed organic layers were dried over anh. MgSO4, filtered, and concentrated to dryness under reduced pressure. Purification by FC (DCM/MeOH=30/1) afforded rac-(S*)-5-(2,6-dimethoxyphenyl)-3-methylene-1-(4-(trifluoromethoxy)benzyl)pyrrolidin-2-one as a colorless oil. LC-MS (conditions A): tR=0.93 min.; [M+H]+: 408.29 g/mol.

Provenance & Evidence