Palladium-Catalyzed Asymmetric Allylic Alkylations with Toluene Derivatives as Pronucleophiles

The first two highly enantioselective palladium‐catalyzed allylic alkylations with benzylic nucleophiles, activated with Cr(CO)3, have been developed. These methods enable the enantioselective synthesis of α‐2‐propenyl benzyl motifs, which are important scaffolds in natural products and pharmaceuticals. A variety of cyclic and acyclic allylic carbonates are competent electrophilic partners furnishing the products in excellent enantioselectivity (up to 99 % ee and 92 % yield). This approach was employed to prepare a nonsteroidal anti‐inflammatory drug analogue. Der weiche Weg: Die Koordination der Tricarbonylchrom‐Gruppe an Toluolderivate erleichtert deren Deprotonierung durch ein Lithiumsilylamid und modifiziert außerdem die „Härte” der resultierenden Lithiumbenzylspezies, sodass diese hoch enantioselektive palladiumkatalysierte allylische Alkylierungen eingehen kann.