TMSCF₃-Mediated Conversion of Salicylates into α,α-Difluoro-3-coumaranones: Chain Kinetics, Anion-Speciation, and Mechanism.

ABSTRACT: As reported by Zhao, the TBAT ([Ph₃SiF₂]^-[Bu₄N]⁺)-initiated reaction of ethyl salicylate with TMSCF₃ in THF generates α,α-difluoro-3-coumaranones via the corresponding O-silylated ethoxy ketals. The mechanism has been investigated by in situ ¹⁹F and ²⁹Si NMR spectroscopy, CF₂-trapping, competition, titration, and comparison of the kinetics with the 3-, 4-, 5-, and 6-fluoro ethyl salicylate analogues and their O-silylated derivatives. The process evolves in five distinct stages, each arising from a discrete array of anion speciations that modulate a sequence of silyl-transfer chain reactions. The deconvolution of coupled equilibria between salicylate, [CF₃]^-

SUBMITTER: Minshull HB 

PROVIDER: S-EPMC10729029 | biostudies-literature | 2023 Dec

REPOSITORIES: biostudies-literature