[carop]

I am trying to understand the mechanism for organocatalytic ring opening polymerization of cyclic carbonates. I have a R-OH added with a cyclic carbonate, with trifluoromethylphenylcyclohexylthiourea (TU) and diazabicycloundecene (DBU), in presence of DCM.

I was thinking that there is some type of carbonyl attack from the R-OH. The DBU gets protonated, leaving the alcohol negatively charged. Then, this acts as a neuclophile to attack the electropositive carbon.



Does that look right? What do the TU and DCM do in the reaction?