Fig. 2: Radical conversion and α-hydrogenation of the MxTTM series.
a Schematic illustration of the reaction steps involved in radical conversion followed by α-hydrogenation. b Deprotonation of the αH precursor followed by one-electron oxidation in DMSO-d6/THF-d8 3:1 (v/v) mixture. Partial 1H NMR spectra of the αH precursors (black lines), carbanions (teal lines) and radicals (red lines). c α-Hydrogenation of the radical in DMSO-d6/THF-d8 1:1 (v/v) mixture. Partial 1H NMR spectra of the radicals (red lines) and their α-hydrogenated products (black lines). No carbanion species was observed in the reverse reaction. The green letters indicate aromatic protons and their corresponding 1H signals. Mesityl substituted chlorophenyl ring protons are distinguished from the non-mesitylated ones by their upfield shifts, as indicated by the apostrophes. The blue arrows illustrate a systematic downfield shift of the αH signal along with increasing mesityl substitution. All spectra are referenced against 1,3,5-trimethoxybenzene (1H, 6.09 ppm) as the internal standard.
