Substrate Self-Assisted Secondary Bond Activation of Allylic Alcohol in a Tsuji-Trost Reaction Revealed by NMR Methods.

The first experimental evidence for the palladium-catalyzed secondary bond activation of allylic alcohols in a Tsuji-Trost reaction was provided by NMR methods, such as variable-temperature 1H NMR, diffusion-ordered spectroscopy (DOSY), Job's method, 1H NMR titration, and nuclear Overhauser enhancement spectroscopy (NOESY). The experimental results revealed that the substrate self-assisted activation of allylic alcohols is probably performed via a 1:1 binding six-membered-ring complex, which are formed by the formation of the secondary bonds, the hydrogen bond and P···O noncovalent bond between allylic alcohol and phosphonium ylide.