Synthesis of Selectively Substituted or Deuterated Indenes via Sequential Pd and Ru Catalysis.

A strategy for the synthesis of functionalized indenes is presented. The readily available substituted phenols are used as starting materials in the reaction sequence composed of Pd-catalyzed Suzuki coupling and Ru-catalyzed ring-closing metathesis, thus representing a practical method for the controlled construction of functionalized indene derivatives. The methodology has been successfully applied to a broad range of substrates, producing substituted indenes in excellent yields. This approach is also utilized for the synthesis of substituted indenes selectively deuterated in position 3, which are rare in literature.