Methylamine → Tert-butyl 2-((methylamino)methyl)pyrrolidine-1-carboxylate

To a suspension of 2-formyl-pyrrolidine-1-carboxylic acid tert-butyl ester (2.68 g) in methanol (30 mL) at room temperature was added a solution of methylamine (831 mg) in methanol (3 mL). The reaction mixture was stirred at room temperature for 72 h and then sodium borohydride (760 mg) and molecular sieves were added. After stirring at room temperature for 2 h, the reaction mixture was filtered and the filtrate reduced in vacuo. The residue was redissolved in dichloromethane (30 mL) and washed with saturated sodium bicarbonate solution (30 mL). The combined organics were washed with brine (30 mL), dried (MgSO4) and reduced in vacuo to give 2-methylaminomethyl-pyrrolidine-1-carboxylic acid tert-butyl ester as a pale yellow oil (2.56 g).