Iron-catalyzed indirect hydration of alkynes in presence of methanesulfonic acid

We have demonstrated that the FeCl2·4H2O and methanesulfonic acid systems show high reaction efficiency for the indirect hydration of various alkynes in DCE. The reaction proceeds under mild conditions to produce various ketones from alkynes. A mechanistic study of the reaction intermediates showed that the alkyne was readily converted into vinyl sulfonate corresponding to the addition of MsOH to the C–C triple bonds, which in turn was transformed to the ketone in the presence of MsOH.