Silver catalyzed substitution of allylic and benzylic alcohols having unactivated hydroxy groups

The catalytic Friedel-Crafts substitution of allylic and benzylic alcohols having free hydroxy groups was regioselectively catalyzed by cationic Ag(I) salts. No precautions to exclude moisture or atmosphere were necessary, making the reaction highly robust and facile. Substitution of allylic alcohols with electron rich aromatic nucleophiles favored products with alkenes conjugated to aromatic substituents. Benzylic substitution was impacted by the electronics of the alcohol aryl group, whereas allylic substitution was not. The use of a bromoindole nucleophile allowed for a formal total synthesis of echinosulfonic acid D, where the penultimate synthetic intermediate was synthesized in half the steps previously needed.