Scheme 3.

Four step model for the intermediates observed via CCD 340–700 nm and ¹⁹F-NMR spectrometry. The first three reaction steps (orange box) were observed for a range of BCF₃ concentrations and analyzed globally by numerical integration at a single wavelength (567 nm). The rate constants associated with the second and third steps (green box) were derived from CCD data using singular value decomposition (SVD). The data for the last step (blue box) were acquired with ¹⁹F-NMR spectrometry and analyzed using SVD.