1-O-benzyl 2-O-methyl (2R,4S)-4-hydroxypyrrolidine-1,2-dicarboxylate

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

Procedure: Compound 19 (1.28 g, 4.6 mmol) dissolved in DCM (20 ml) is added dropwise into CDI (0.75 g, 4.6 mmol) solution in DCM (30 ml). After stirring for 2 hr, 1,2,3,4-tetrahydroisoquinoline (0.644 ml, 4.6 mmol) is added and the mixture is stirred over night. The solvent is removed and residue applied to flash chromatography on silica gel (Hex/ethyl acetate, 2/1 to 1/1). Compound 20 (1.8 g, 90%) is obtained as pale yellow syrup. the mixture is stirred over night The solvent is removed