Exploring the PES of the Staudinger Reaction between (CH3)2CHCH2N3 and (CH3)3P by DFT Method

The potential energy surface of the staudinger reaction of substituted phosphine and an organic azide has been investigated by using Density Functional Theory. Fourteen stationary points related to three different pathways have been located. The different pathways are cis initial attack, trans initial attack and concerted attack, respectively. According to our results the order of the first step energy barrier is Ea cis-attack < Ea con-attack < Ea trans-attck  Therefore, the reaction pathway with the cis initial attack dominate the staudinger reaction. The trans attack to terminal nitrogen atom and the one- step pathway of the phosphorous atom attacking the substituted nitrogen are unfavorable energetically. Also, the cis attack consists of three steps, among them, the second one which is a process to form the four membered ring, has the largest energy barrier.