Catalytic Enantioselective β-Alkylation of α,β-Unsaturated Aldehydes by Combination of Transition-Metal- and Aminocatalysis: Total Synthesis of Bisabolane Sesquiterpenes
aldehydes by combination of simple chiral amine and copper catalysts provides β‐branched aldehydes in a one‐pot protocol (see scheme). The methodology was applied to the short total syntheses of bisabolanesesquiterpenes (S)‐(+)‐curcumene, (E)‐(S)‐(+)‐3‐dehydrocurcumene and (S)‐(+)‐tumerone.
amine organocatalysts and their application to the asymmetric transfer hydrogenation of α,β-unsaturatedaldehydes are disclosed. A lower catalytic loading (5 mol %) is demonstrated for the reduction of a wide range of α,β-unsaturatedaldehydes (up to 97% yield and up to 99% ee). The application of this scalable methodology is showcased for the asymmetric synthesis of bioactive molecules such as phenoxanol