Pyrrole anion addition to carbon disulfide: An ab initio study

The reaction pathways of pyrrole-1- and pyrrole-2-carbodithioate anions formation were studied using the MP2/6-31+G* approach. No activation barrier was found on the potential energy surface for the former. By contrast, there is a significant activation barrier on the C2-adduct formation pathway. This can cause a kinetic formation of the thermodynamically less favorable N-adduct from unsubstituted pyrrole and CS2, while a relative instability of 2(5)-methylpyrrole-1-carbodithioates results in C2- and C3-adducts. (C) 2004 Wiley Periodicals, Inc.