FIGURE 7.

¹³C NMR analysis of the Ta1305 reaction product. A, signal at 70.9 ppm in the NMR spectrum of a pre-reaction mixture is assigned to the C3 of [U-¹³C]MVA. It exhibits an apparent quartet coupling pattern (J = ∼38 Hz). Smaller signals around it probably come from other components in the reaction mixture. B, corresponding signal at 78.5 ppm in the spectrum of a post-reaction mixture has acquired an additional hyperfine two-bond ¹³C-³¹P coupling (J = 8 Hz), which results in a quartet-doublet coupling pattern.