Kinetic Analysis and Sequencing of Si-H and C-H Bond Activation Reactions: Direct Silylation of Arenes Catalyzed by an Iridium-Polyhydride

Esteruelas, M.A. ; Martínez, A. ; Oliván, M. ; Oñate, E.

Resumen: The saturated trihydride IrH3{¿3-P, O, P-[xant(PiPr2)2]} (1; xant(PiPr2)2 = 9, 9-dimethyl-4, 5-bis(diisopropylphosphino)xanthene) coordinates the Si-H bond of triethylsilane, 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane, and triphenylsilane to give the s-complexes IrH3(¿2-H-SiR3){¿2-cis-P, P-[xant(PiPr2)2]}, which evolve to the dihydride-silyl derivatives IrH2(SiR3){¿3-P, O, P-[xant(PiPr2)2]} (SiR3 = SiEt3 (2), SiMe(OSiMe3)2 (3), SiPh3 (4)) by means of the oxidative addition of the coordinated bond and the subsequent reductive elimination of H2. Complexes 2-4 activate a C-H bond of symmetrically and asymmetrically substituted arenes to form silylated arenes and to regenerate 1. This sequence of reactions defines a cycle for the catalytic direct C-H silylation of arenes. Stoichiometric isotopic experiments and the kinetic analysis of the transformations demonstrate that the C-H bond rupture is the rate-determining step of the catalysis. As a consequence, the selectivity of the silylation of substituted arenes is generally governed by ligand-substrate steric interactions.

Idioma: Inglés

DOI: 10.1021/jacs.0c07578

Año: 2020

Publicado en: Journal of the American Chemical Society 142, 45 (2020), 19119-19131
ISSN: 0002-7863

Factor impacto JCR: 15.419 (2020)

Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 15 / 178 = 0.084 (2020) - Q1 - T1

Factor impacto SCIMAGO: 7.115 - Biochemistry (Q1) - Colloid and Surface Chemistry (Q1) - Chemistry (miscellaneous) (Q1) - Catalysis (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E06-20R
Financiación: info:eu-repo/grantAgreement/ES/DGA/LMP148-18
Financiación: info:eu-repo/grantAgreement/ES/MINECO-AEI-FEDER/CTQ2017-82935-P
Financiación: info:eu-repo/grantAgreement/ES/MINECO-AEI-FEDER/RED2018-102387-T

Tipo y forma: Article (PostPrint)