Triethylamine → (R)-1-Boc-2-methylpyrrolidine

Participants

Reaction Steps

A heterogenous reaction mixture of 2-(S)-iodomethyl-pyrrolidine-1-carboxylic acid tert butyl ester (compound (4) obtained from above, 25 g, 0.08 mol), triethylamine (11.2 mL, 8.12 g, 0.08 mol) in methanol (250 mL) and 5% palladium on carbon (2.5 g, 10 wt %, Pd/C) was allowed to react at room temperature under a blanket of hydrogen gas overnight and until HPLC showed less than 1% starting material (˜7 hours). The reaction mixture was filtered and the filtrate was concentrated to a residue. The residue was dissolved in distilled water (100 mL) and ethyl acetate (100 mL). The organic layer was separated and the aqueous layer was re-extracted with ethyl acetate (2×50 mL). The combined organic layer was washed with 1 M aqueous H3PO4 (2×100 mL) followed by saturated NaHCO3 (233 100 mL), dried over MgSO4, filtered, and concentrated to leave an oily residual product (12.78 g, 85.9% yield). 1H NMR (CDCl3): δ 1.16 (d, 3H, CH3), 1.47 (s, 9H, 3×CH3), 1.50–1.82 (m, 2H, CH2), 1.84–2.03 (m, 2H, CH2 ), 3.34 (m, 2H, CH2) and 3.86 (m, 1H, CH); [M+H]+ at m/z 186.

Provenance & Evidence