Bottom‐Up Synthesis of Acrylic and Styrylic RhII Carboxylate Polymer Beads: Solid‐Supported Analogs of Rh2(OAc)4

Abstract

We have developed a short and efficient bottom‐up synthesis of acrylic and styrylic polymer beads containing dirhodium(II) tetracarboxylates. The solid supported dirhodium(II) tetracarboxylate catalysts were synthesized in as little as two steps overall from dirhodium tetratrifluoroacetate and commercially available carboxylic acids, making the bottom‐up approach a viable alternative to the post‐modification approach commonly used. The dirhodium(II) tetracarboxylate polymer beads have a convenient size (ca. 100 µm), are easy to handle, and can be considered solid‐supported analogs of Rh2(OAc)4. Beads generated from dirhodium(II) tetracarboxylates with four polymerizable carboxylate ligands displayed the best catalytic performance and compared favorably to Rh2(OAc)4 in benchmarked cyclopropanation reactions. The results imply that the cumbersome synthesis of monomeric dirhodium(II) tetracarboxylates with mixed ligands systems can be avoided and that immobilized dirhodium(II)‐catalysts with a higher degree of crosslinking is a viable option to catalysts linked in an anchor‐like fashion. We demonstrate recovery and recycling, and a potential use of the beads as catalysts in a cyclopropanation reaction towards the insecticide chrysanthemic acid.