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Consecutive C-F bond activation and C-F bond formation of heteroaromatics at rhodium: the peculiar role of FSi(OEt)₃.

ABSTRACT: C-F activation of 2,3,5,6-tetrafluoropyridine at [Rh{Si(OEt)₃}(PEt₃)₃] (1) yields [Rh{2-(3,5,6-C₅F₃HN)}(PEt₃)₃] (2) and FSi(OEt)₃, but in an unprecedented consecutive reaction FSi(OEt)₃ acts as a fluoride source to give [Rh(4-C₅F₄N)(PEt₃)₃] (4) by regeneration of the C-F bond and C-H activation. Analogous refluorination steps were observed for other 2-pyridyl rhodium complexes. NMR spectroscopic studies revealed a delicate balance between the feasibility for C-F bond formation accompanied by a C-H activation and the occurrence of competing reactions such as hydrodefluorinations induced by the intermediary presence of H₂.

SUBMITTER: Raza AL

PROVIDER: S-EPMC5707480 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature

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Consecutive C-F bond activation and C-F bond formation of heteroaromatics at rhodium: the peculiar role of FSi(OEt)3.

Raza A L AL Braun T T

Chemical science 20150526 7

C-F activation of 2,3,5,6-tetrafluoropyridine at [Rh{Si(OEt)3}(PEt3)3] (1) yields [Rh{2-(3,5,6-C5F3HN)}(PEt3)3] (2) and FSi(OEt)3, but in an unprecedented consecutive reaction FSi(OEt)3 acts as a fluoride source to give [Rh(4-C5F4N)(PEt3)3] (4) by regeneration of the C-F bond and C-H activation. Analogous refluorination steps were obs ...[more]

PMID: 29218192

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