1-Chloroethyl chloroformate → (3S,4R)-methyl 4-(3,4-dichlorophenyl)pyrrolidine-3-carboxylate

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Reaction Steps

1-Chloroethyl chloroformate (1.5 mL, 13.9 mmol) was added to a solution of (3S,4R)-methyl 1-benzyl-4-(3,4-dichlorophenyl)pyrrolidine-3-carboxylate (4.20 g, 11.5 mmol) in DCE (50 mL) at 0° C. The mixture was refluxed for 1 hour. After cooling, the solvent was removed under vacuum at 65° C. for 1 hour. MeOH (50 mL) was added to the residue and refluxed for 1 hour. The MeOH was removed. The solid was redissolved in CHCl3 and treated with saturated Na2CO3. The aqueous layer was separated and extracted with CHCl3 (2×30 mL). The organic phase was combined and dried. The solvent was removed to afford (3S,4R)-methyl 4-(3,4-dichlorophenyl)pyrrolidine-3-carboxylate (3.1 g, 98%). (LCMS (APCI+) [M+H]+ 274.1; Rt: 2.25 min.).

Provenance & Evidence