| Autor: |
Holmsen MSM; Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France.; Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1126 Blindern, N-0316 Oslo, Norway.; Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway., Blons C; Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France., Amgoune A; Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France., Regnacq M; Institut Parisien de Chimie Moléculaire - IPCM UMR 8232, CNRS/Sorbonne Université, 4 Place Jussieu, CC 229, 75252 Paris Cedex 05, France., Lesage D; Institut Parisien de Chimie Moléculaire - IPCM UMR 8232, CNRS/Sorbonne Université, 4 Place Jussieu, CC 229, 75252 Paris Cedex 05, France., Sosa Carrizo ED; CNRS/Université de Pau et des Pays de l'Adour, E2S-UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - IPREM UMR 5254, Hélioparc. 2 Avenue du Président Angot, 64053 Pau Cedex 09, France., Lavedan P; Institut de Chimie de Toulouse - ICT, CNRS/Université de Toulouse, UPS, 118 Route de Narbonne, 31062 Toulouse Cedex 09, France., Gimbert Y; Institut Parisien de Chimie Moléculaire - IPCM UMR 8232, CNRS/Sorbonne Université, 4 Place Jussieu, CC 229, 75252 Paris Cedex 05, France.; Département de Chimie Moléculaire - DCM UMR 5250, CNRS/Université Grenoble Alpes, UGA, 38000 Grenoble, France., Miqueu K; CNRS/Université de Pau et des Pays de l'Adour, E2S-UPPA, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - IPREM UMR 5254, Hélioparc. 2 Avenue du Président Angot, 64053 Pau Cedex 09, France., Bourissou D; Laboratoire Hétérochimie Fondamentale et Appliquée - LHFA UMR 5069, CNRS/Université de Toulouse, UPS, 118 route de Narbonne, 31062 Toulouse Cedex 09, France. |
| Abstrakt: |
Over the last 5-10 years, gold(III) catalysis has developed rapidly. It often shows complementary if not unique features compared to gold(I) catalysis. While recent work has enabled major synthetic progress in terms of scope and efficiency, very little is yet known about the mechanism of Au(III)-catalyzed transformations and the relevant key intermediates have rarely been authenticated. Here, we report a detailed experimental/computational mechanistic study of the recently reported intermolecular hydroarylation of alkynes catalyzed by (P,C)-cyclometalated Au(III) complexes. The cationic (P,C)Au(OAc F ) + complex (OAc F = OCOCF 3 ) was authenticated by mass spectrometry (MS) in the gas phase and multi-nuclear NMR spectroscopy in solution at low temperatures. According to density functional theory (DFT) calculations, the OAc F moiety is κ 2 -coordinated to gold in the ground state, but the corresponding κ 1 -forms featuring a vacant coordination site sit only slightly higher in energy. Side-on coordination of the alkyne to Au(III) then promotes nucleophilic addition of the arene. The energy profiles for the reaction between trimethoxybenzene (TMB) and diphenylacetylene (DPA) were computed by DFT. The activation barrier is significantly lower for the outer-sphere pathway than for the alternative inner-sphere mechanism involving C-H activation of the arene followed by migratory insertion. The π-complex of DPA was characterized by MS. An unprecedented σ-arene Au(III) complex with TMB was also authenticated both in the gas phase and in solution. The cationic complexes [(P,C)Au(OAc F )] + and [(P,C)Au(OAc F )(σ-TMB)] + stand as active species and off-cycle resting state during catalysis, respectively. This study provides a rational basis for the further development of Au(III) catalysis based on π-activation. |
