In 2013 Wagner and coworkers predicted the barrier heights to the formation of carbamates given a small variety of substituted isocyanates (RNCO, R=CH 3 , CH 2 F, C 6 H 5 , SiH 3 , SiH 3 CH 2 ) with the B3LYP/6-31G* method. They determined that greater electron withdrawing substituents on the RNCO molecule lowered the barrier to carbamate formation. However, Wagner and coworkers only consider the reaction across the N --C double bond and exclude any mention of how substituents influence reaction across the C --O double bond.