[Br:1][C:2]1[CH:3]=[C:4]([N:8]2[C:12](=[O:13])[C@H:11]3[C@@H:14]([Si](C)(C)C)[S:15][CH2:16][C@H:10]3[C:9]2=[O:21])[CH:5]=[CH:6][CH:7]=1.[F-].[Cs+].O.C1C=CC=CC=1>CN(P(N(C)C)(N(C)C)=O)C.O>[Br:1][C:2]1[CH:3]=[C:4]([N:8]2[C:9](=[O:21])[C@@H:10]3[CH2:16][S:15][CH2:14][C@@H:11]3[C:12]2=[O:13])[CH:5]=[CH:6][CH:7]=1To a solution of (3S,3aS,6aR)-5-(3-bromo-phenyl)-3-trimethylsilanyl-tetrahydro-thieno[3,4-c]pyrrole-4,6-dione (637 mg, 1.66 mmol) in HMPA (5 ml) and water (2 drops) was added powdered cesium fluoride (254 mg, 1.66 mmol). The mixture was heated (80° C., oil bath) for 8 hours and then stirred over night at ambient. Water (50 ml) and benzene (60 ml) were added and the material was shaken. The organic phase was collected and washed with brine (50 ml). The benzene phase was collected and the aqueous phase was back-extracted (2×40 ml) with benzene. The organics were combined, dried (MgSO4), filtered and stripped. The remainder was purified by silica gel chromatography eluting with 4% to 45% ethyl acetate in hexanes to afford 290 mg of (3aR,6aS)-5-(3-bromo-phenyl)-tetrahydro-thieno[3,4-c]pyrrole-4,6-dione, as a brown-yellow solid.
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