Fig. 3: Structural characterization of two conformers.

a Comparison of the ¹H NMR (400 MHz, CDCl₃, 298 K) spectra of two products (top: 40 eq. zinc; bottom: 10 eq. zinc; inset: fluorescence images excited by UV-365 nm, scale bar: 1 cm). b yields of two products (blue conformer and green conformer) under varying zinc amounts (5–40 eq. zinc).