Experimental procedure¹⁾: the amine (0.5 mmol) is added neat to a solution of 1,3-bis(tert-butoxycarbonyl)-2-(trifluoromethanesulfonyl)guanidine (1, 0.45 mmol) and triethylamine (70 µL, 0.5 mmol) in dichloromethane (2 mL), and the mixture is stirred at rt until all 1 is consumed as evidenced by TLC. After completion of the reaction, the mixture is diluted with dichloromethane (3 mL) and washed with 2 mol/L sodium bisulfate, saturated sodium bicarbonate, and brine. After drying with sodium sulfate and filtering the solvent is removed under reduced pressure. If desired, the crude products may be further purified by flash chromatography.

Experimental procedure¹⁾: the amine (0.5 mmol) is added neat to a solution of 1,3-bis(tert-butoxycarbonyl)-2-(trifluoromethanesulfonyl)guanidine (1, 0.45 mmol) and triethylamine (70 µL, 0.5 mmol) in dichloromethane (2 mL), and the mixture is stirred at rt until all 1 is consumed as evidenced by TLC. After completion of the reaction, the mixture is diluted with dichloromethane (3 mL) and washed with 2 mol/L sodium bisulfate, saturated sodium bicarbonate, and brine. After drying with sodium sulfate and filtering the solvent is removed under reduced pressure. If desired, the crude products may be further purified by flash chromatography.