Reagent Control Enables Selective and Regiodivergent Opening of Unsymmetrical Phenonium Ions

We report the first
examples of selective and regiodivergent opening
of unsymmetrical phenonium ions with chloride ions. These reactions
are enabled by the dual role of SnCl4 and TiCl4 as Lewis acids and chloride nucleophiles. Reagent control dictates
addition of chloride at either the substituted internal position (SnCl4) or unsubstituted terminal position (TiCl4) of
the phenonium ion. These reactions are highly selective, stereospecific,
operationally simple, and proceed in good to excellent yields. Diverse
product utility is demonstrated.