Ir-catalyzed Allylic Alkylation Research Articles

Combining Enantioselective Rh-Catalyzed Conjugate Addition and Ir-Catalyzed Allylic Alkylation in Stereodivergent, Multicomponent Coupling Reactions to Form Three Stereocenters.

Stereodivergent dual catalysis has emerged as a powerful tool to selectively prepare all four stereoisomers in molecules containing two chiral centers from common starting materials. Most processes involve the use of two substrates, and it remains challenging to use dual catalyst approaches to generate molecules having three newly formed stereocenters with high diastereo- and enantioselectivity. Here we report a multicomponent, stereodivergent method for the synthesis of targets containing three contiguous stereocenters by the combination of enantioselective Rh-catalyzed conjugate addition and Ir-catalyzed allylic alkylation methodologies. Both cyclic and acyclic α,β-unsaturated ketones undergo β-arylation using aryl boron reagents to form an enolate nucleophile that can be subsequently allylated at the α-position. The reactions proceed often with >95 % ee and with >90 : 10 dr. Epimerization at the α-carbonyl center enables the preparation of any of the eight possible stereoisomers from common starting materials, as demonstrated for cyclohexanone products.

Enantioselective Ir-Catalyzed Allylic Alkylation of Racemic Allylic Alcohols with Malonates.

Ir-catalyzed enantioselective allylic alkylation of branched racemic allylic alcohols with malonates is described. Enabled by Carreira's chiral Ir/(P, olefin) complex, the method described allows allylic substitution with various aromatic alcohols and malonates with excellent enantioselectivity. The malonates could be used directly as efficient nucleophiles without the need of preactivation.

Regio- and Enantioselective Ir-Catalyzed Allylic Alkylation

Regio- and Enantioselective Ir-Catalyzed Allylic Alkylation

Enantioselective Construction of Spiroindolenines by Ir-Catalyzed Allylic Alkylation Reactions

With 2-methyl-1,2,3,4-tetrahydroquinoline-derived phosphoramidite ligand (R,R(a))-L(6), Ir-catalyzed intramolecular C-3 allylic alkylation of indoles has been realized to afford highly enantioenriched spiroindolenine derivatives in 92-98% yields with up to >99/1 dr and 97% ee.