The Sarcosine NCA was synthesized as was described previously . Sarcosine 5.00 g (0.056 mol, 1.7 eq.) pre-dried by azeotropic distillation with toluene was placed in 250 mL dried Schlenk flask and suspended in 90 mL of dry THF under a steady flow of argon followed by the addition of 4.0 mL (0.033 mol, 1.0 eq.) diphosgene via syringe. The continuous flow of argon was turned off, and the reaction mixture was heated to 66 °C. The reaction vessel was equipped with a washing bottle containing 35 wt. % KOH solution to neutralize the developing HCl. Stirring and heating were continued until all solid was dissolved, and the dark brown solution was obtained (around 3.0 h). The solvent was evaporated under reduced pressure, yielding a brownish oil as a crude product. 5.0 mL of dry petrol ether was added to the obtained product under a steady argon flow and left in the fridge overnight to solidify. The solid was decanted under an argon atmosphere, dried under reduced pressure, and subsequently sublimated in vacuo (4.00 g, 80 %).