Synthesis of NHC Ligands Containing a Sulfoxide Moiety and Their Use in Cross-Coupling via a Au(I)/(III) Catalytic Cycle
作者:Takanori Shibata、Rikako Nagai、Sari Okazaki、Shun Nishibe、Mamoru Ito
DOI:10.1246/bcsj.20220013
日期:2022.4.15
We designed and synthesized a new series of NHCs with a sulfoxide moiety as a hemilabile ligand. We investigated the catalytic activities of Au(I)-NHC complexes in the strong oxidant-free cross-coupling of iodoarenes with 1,3,5-trimethoxybenzene. We ascertained that the sulfoxide moiety is critical for the Au(I)/(III) catalytic cycle.
A new copper-mediated cross-coupling of arenes and arylboronic acids is described. Under the influence of Cu(OCOCF3)(2), the C-H bond arylation of electron-rich arenes with arylboronic acids takes place to afford a range of biaryis in good yields. The reaction is selective for cross-coupling; no homocoupling product arising from arenes or arylboronic acids is detected. Multiple C-H bond arylation is possible with indoles and pyrroles furnishing interesting extended pi-systems.