Asymmetric Allylation of Furfural Derivatives: Synergistic Effect of Chiral Ligand and Organocatalyst on Stereochemical Control

An asymmetric allylation reaction at the benzylic position of furfurals that are easily accessed from 5-HMF, which is a biomass derivative, has been established by palladium and amine cooperative catalysis. The high levels of enantioselectivity of up to 97% enantiometric excess (ee) were enabled by the synergistic stereochemical control of a chiral TADDOL-based phosphoramidite ligand and a chiral diphenylprolinol silyl ether. The product could be feasibly transformed to chiral aryl substituted spiroacetal via a four-step reaction sequence.