Propanal → Methyl (-)-(S)-1-propyl-2-pyrrolidinecarboxylate

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Reaction Steps

Methyl (S)-2-pyrrolidinecarboxylate hydrochloride (1.65 g, 0.01 mol) was added to a hydrogenation flask containing a mixture of propionaldehyde (2.4 g, 0.04 mol), 5% Pd/C (0.3 g) and 30 ml MeOH. The mixture was shaken an a Parr apparatus at 40 psi hydrogen pressure for 2 h at room temperature. After filtration and evaporation the residue was mixed with 10 ml 2M HCl and 40 ml ice-water and then extracted twice with ET2O. Solid NaCl was added to the aqueous phase which was made alkaline with 20 ml 2M NH3 during addition of ice. Extraction with Et2O twice, drying (MgSO4) and evaporation afforded 1.8 g of the title compound, which was used directly in Example 11A. [α]D25 =-85° (c=1.3, CHCl3); MS (EI, 70 eV): m/z (rel.int.) 171(M, 1.9%), 112(100%).

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