For activities with increasing concentrations of substrate and co-solvent 2-propanol, reactions were performed under standard conditions. A constant azide concentration of 40 mM was used with different concentrations of substrate 1 (5, 10, 20, 50, 100, 150, or 200 mM). Sampling and achiral GC analysis were performed after 4 and 24 h. Reactions were performed in duplicates.