New recoverable poly(ethylen glycol)-supported C1-diamino-oligothiophene ligands for Pd-promoted asymmetric allylic alkylation reactions

A new class of chiral C1-symmetry diamino-oligothiophene ligands easy-grafted on a soluble polymeric support (MeOPEG5000) is described. The diamines were found to be effective promoting agents for the [Pd(0)]-catalysed asymmetric allylic alkylation (AAA) of dimethyl malonate in high yields and excellent enantioselectivity (ee up to 99%). The supported chiral ligand readily recovered by precipitation and filtration was recycled up to three times without appreciable loss in activity. The recycle of the organometallic catalytic system was also investigated.