Step 6: Boc-1-methylcyclopropanesulfonamide 2d6 (151.8 mg, 0.65 mmol) was dissolved in dichloromethane (6 mL) and trifluoroacetic acid (6 mL) was added slowly. The reaction mixture was stirred at room temperature for 3.5 hours. Upon completion of the reaction, the solvent was removed by high vacuum evaporation to afford the deprotected product 2d7 as an off-white waxy solid (79.1 mg, 91% yield). The structure of the product was confirmed by 1H NMR (CDCl3, 400 MHz): δ 4.56 (s, 2H), 1.58 (s, 3H), 1.43-1.38 (m, 2H), 0.85-0.80 (m, 2H).
