Figure 3.

¹H NMR (250 MHz) spectra of fluorination reaction mixtures diluted with CDCl₃ and filtered. a) Full range spectrum with signals from substrate 1 and product 1-F. The catalyst was Cp₂Ti(OTf)₂. Signals resulting from F–TEDA or H–TEDA are missing because of the insolubility of those species in CDCl₃. The signals for MeCN and its ¹³C-satellites have been cut for clarity. b) Reaction progress monitoring after 28 h (region 3.9–4.3 ppm) in catalytic reactions with the Lewis acids indicated, along with the results from a blank experiment.