Extended Data Fig. 1: Identification of S-VG products.

a,b, HPLC analysis of purified S-VGs and a S-VG mixture from the α-arylation (syringolation) of VG. The purified mS-V′G and pS-V′G were obtained by flash-column separation of the S-VG mixture from the syringolation reaction. The purified mS-VG and pS-VG were obtained by deformylation of the purified mS-V′G and pS-V′G. The syringolation reaction condition: VG (0.25 mmol); syringol (0.75 mmol, 3 equiv.) in 5 mL of 88 wt% formic acid; reaction time, 1 h; reaction temperature, 80 °C. c, ¹H–¹³C HSQC NMR spectra of VG, purified S-VG isomers, and the crude mixture of S-VGs after the syringolation reaction under the typical condition.