Catalytic role of amines in activation of PhICl2 from a computational point of view.

We thoroughly investigated mechanistic features of dichlorination of diazoacetates using PhICl2 catalysed by pyridine. We found that the pyridine serves as a catalyst for decomposition of PhICl2 to PhI and Cl2, leading to the dichlorination step being driven by the in situ generated Cl2. This type of activation was found to be applicable to other amine-catalysed chlorination reactions using PhICl2.