PEG-Supported Chiral Diamine Ligand for Pd-Catalyzed Allylic Alkylation

Significance

Poly(ethylene glycol)-supported diaminooligothiophene was prepared and used as a chiral ligand in the palladium-catalyzed asymmetric allylic alkylation. The polymer-supported diamino­oligothiophene 3 was prepared by the reaction of the diaminooligothiophene 1 with poly(ethylene glycol) mesylate 2 (eq. 1). The asymmetric allylic alkylation of allyl carbonates with dimethyl malo­nate took place in the presence of allylpalladium(II) chloride dimer and the polymer-supported ligand 3 to give the allylic alkylated adducts in 50-90% yield with 78-95% ee (eq. 2). The polymeric palladium complex is dissolved in CH₂Cl₂ to provide a homogeneous mixture during the reaction. Ligand 3 was recovered by precipitation and filtration and was reused twice [91% yield, 92% ee (1st reuse), 84 % yield, 92% ee (2nd reuse)].