[Cl:1][C:2]([Cl:13])([Cl:12])[CH:3]1[N:7]2[CH2:8][CH2:9][CH2:10][C@@H:6]2[C:5](=[O:11])[O:4]1.[Li+].[CH3:15]C([N-]C(C)C)C.C1COCC1.CCCCCCC.ICI>C1COCC1>[CH3:15][C:6]12[CH2:10][CH2:9][CH2:8][N:7]1[CH:3]([C:2]([Cl:1])([Cl:12])[Cl:13])[O:4][C:5]2=[O:11]To a solution of (7aR)-3-(trichloromethyl)tetrahydropyrrolo[1,2-c]oxazol-1(3H)-one (D48) (0.2 g, 0.82 mol) in THF (10 ml) cooled at −78° C. LDA 2M sol in THF/heptane (0.58 ml, 1.17 mol) was added and the mixture stirred 30 min. Diiodomethane (0.185 ml, 2.97 mol) was added and the temperature was allowed to warm to −40° C. over a period of 2 hrs then left at this temperature for an additional hour. The resulting mixture was partitioned between DCM and H2O. The aqueous phase was extracted with DCM (2×10 ml); the organic phases were collected, dried over Na2SO4 and evaporated in vacuo. The residue was purified by SPE-Si cartridge (25 g) eluting with DCM. Collected fractions after solvent evaporation afforded title compound (D49) in mixture (4:1) with starting material (110 mg).
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