Transition-metal-catalyzed asymmetric Tsuji–Trost reactions are among the most widely used name reactions in organic synthesis.1 However, it remains still challenging in preparing chiral Z-olefins via this type of reactions. The reason lies in the thermodynamic instability of the key intermediate in such reactions, anti-π-allyl transition-metals, which are readily transformed into the counterparts in the syn configuration prior to the capture of external nucleophiles.2 Recently, we realized the Z-retentive asymmetric allylic substitution reactions under Ir- or Pd-catalysis by capturing the transient anti-π-allyl transition-metals with highly reactive nucleophiles.3 Combined computational and experimental investigations into the reaction mechanism were carried out, including kinetic measurement on anti-to-syn isomerization, isolation and characterization of key intermediates, asymmetric induction model, etc. Such mechanistic insights laid the foundation for rational designs of novel asymmetric allylic substitution reactions towards advanced chiral Z-olefins.-

allylic substitution,Reaction mechanism,asymmetric catalysis