<i>anti</i>-Hydroarylation of Activated Internal Alkynes: Merging Pd and Energy Transfer Catalysis

Abstract

A general catalytic <i>anti</i>-hydroarylation of electron-deficient internal alkynes compatible with both electron-poor and electron-rich aryl reagents is reported. This selectivity is achieved through a sequential <i>syn</i>-carbopalladation of the alkyne by an Ar-Pd species, followed by a tandem, Ir-photocatalyzed, counter-thermodynamic <i>E</i> → <i>Z</i> isomerization. The use of <i>ortho</i>-substituted boronic acids enables direct access to pharmaceutically relevant heterocyclic cores via a cascade process. Mechanistic insight into the involvement of Ar-Pd versus Pd-H as an active species is provided.