Ligand Postsynthetic Functionalization with Fluorinated Boranes and Implications in Hydrogenation Catalysis

The incorporation of boron functionalities into transition-metal catalysts has become a promising strategy to improve catalytic performance, although their synthesis typically entails the preparation of sophisticated bifunctional ligands. We report here the facile and direct postsynthetic functional...

Descripción completa

Detalles Bibliográficos
Autores: Alférez, Macarena G., Moreno, Juan J., Gaona, Miguel A., Maya, Celia, Campos, Jesús
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2023
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:dnet:digitalcsic_::635b600c85d27a4c4edefa51542bb88c
Acceso en línea:http://hdl.handle.net/10261/340605
Access Level:acceso abierto
Palabra clave:σ-borane complex
Rhodium
Ligand functionalization
Hydrogenation
Pendant borane
Descripción
Sumario:The incorporation of boron functionalities into transition-metal catalysts has become a promising strategy to improve catalytic performance, although their synthesis typically entails the preparation of sophisticated bifunctional ligands. We report here the facile and direct postsynthetic functionalization of rhodium(I) compound [(η5-C9H7)Rh(PPh3)2] (1) by treatment with perfluorinated boranes. Borane addition to 1 results in an unusual C(sp2)-H hydride migration from the indenyl ligand to the metal with the concomitant formation of a C–B bond. In the case of Piers’ borane [HB(C6F5)2], this is followed by a subsequent hydride migration that leads to an unprecedented 1,2-hydrogen shift reminiscent of Milstein’s cooperative dearomatization pathways. Computational investigations provide a mechanistic picture for the successive hydride-migration steps, which enriches the non-innocent chemistry of widespread indenyl ligands. Moreover, we demonstrate that the addition of Piers’ borane is highly beneficial for catalysis, increasing catalyst efficiency up to 3 orders of magnitude.