PhICl2 Is Activated by Chloride Ions

A study on the potential activating role of pyridine in the electrophilic chlorination of anisole by PhICl₂ has led to the discovery that soluble sources of chloride ions activate PhICl₂ in the reaction at catalytic loadings, greatly increasing the rate of chlorination. It is further shown that presence of chloride increases the rate of decomposition of PhICl₂ into PhI and Cl₂. The specific mechanism by which chloride induces electrophilic chlorination and decomposition of PhICl₂ remains an open question.