Progress in Iridium-Catalyzed Asymmetric Allylic Substitution Reactions via Synergetic Catalysis

Iridium-catalyzed asymmetric allylic substitution reaction has become one of the most important methods for the synthesis of chiral compounds due to its exceptional branched regioselectivity and excellent enantioselectivity. The scope of nucleophiles will be further expanded by synergetic catalysis system of iridium and other catalysts (organocatalysts, other transition metal catalysts). Besides, it is possible to improve the enantioselectivity of the reaction and even realize the stereodivergent synthesis of the products with multiple stereocenters. The progress in the field of catalytic asymmetric allylic substitutions through synergetic iridium and organocatalysis or other transition metal catalysis is summarized. These reactions are classified according to the types of catalysts (aminocatalyst, phase transfer catalyst, Bronsted acid, Lewis base, transition metal). Meanwhile, the mechanism of representative reactions, the existing problems and the prospects in this area are briefly described.