Stable Au(I) catalysts for oxidant-free C-H functionalization with iodoarenes
作者:R. Tyler Mertens、Charles E. Greif、James T. Coogle、Gilles Berger、Sean Parkin、Mark D. Watson、Samuel G. Awuah
DOI:10.1016/j.jcat.2022.02.019
日期:2022.4
oxidant-free gold-catalyzed cross coupling reactions involving aryl halides have been hamstrung by the lack of gold catalysts capable of performing oxidative addition at Au(I) centers. Herein, we report the development of novel tricoordinate Au(I) catalysts supported by N,N-bidentate ligands and ligated by phosphine or arsine ligands for C-H functionalization withoutexternaloxidants to form biaryls
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.
AbstractIn the last decade, major advances have been made in homogeneous gold catalysis. However, AuI/AuIII catalytic cycle remains much less explored due to the reluctance of AuI to undergo oxidative addition and the stability of the AuIII intermediate. Herein, we report activation of aryl halides at gold(I) enabled by NHC (NHC=N‐heterocyclic carbene) ligands through the development of a new class of L‐shaped heterobidentate ImPy (ImPy=imidazo[1,5‐a]pyridin‐3‐ylidene) N,C ligands that feature hemilabile character of the amino group in combination with strong σ‐donation of the carbene center in a rigid conformation, imposed by the ligand architecture. Detailed characterization and control studies reveal key ligand features for AuI/AuIII redox cycle, wherein the hemilabile nitrogen is placed at the coordinating position of a rigid framework. Given the tremendous significance of homogeneous gold catalysis, we anticipate that this ligand platform will find widespread application.
5,6,7,12-Tetrahydrodibenz[c,f][1,5]azabismocines: Highly Reactive and Recoverable Organobismuth Reagents for Cross-Coupling Reactions with Aryl Bromides
作者:Shigeru Shimada、Osamu Yamazaki、Toshifumi Tanaka、Maddali L. N. Rao、Yohichi Suzuki、Masato Tanaka