Preparation and Synthetic Applications of [2.2]Paracyclophane Trifluoroborates: An Efficient and Convenient Route to Nucleophilic [2.2]Paracyclophane Cross‐Coupling Building Blocks

Abstract

We report the synthesis of [2.2]paracyclophane (PCP) trifluoroborate building blocks that can be used for the incorporation of the PCP moiety into a wide range of (hetero)aryl chlorides, bromides and triflates by a Pd(II)/RuPhos mediated Suzuki–Miyaura cross‐coupling reaction. The PCP trifluoroborate species are bench stable with extended shelf life and easily accessible on a multigram scale by a two‐step synthesis from commercially available PCP. They can be handled conveniently without special precautions, thus overcoming many of the limitations of other PCP cross‐coupling reagents. Additionally, a high yielding regioselective monolithiation/borylation protocol for the synthesis of pseudo‐para and pseudo‐ortho PCP halotrifluoroborates and their subsequent Suzuki–Miyaura cross‐coupling are described.