Synthesis of Novel Highly Active Thiophene and Benzothiophene Containing Diphosphine Ligands and their Use in the Asymmetric Allylation of Catechol

Abstract

Novel thiophene and benzothiophene containing diphosphine ligands 5-8 with a chiral cyclohexyl diamine backbone have been prepared and used in the asymmetric allylation of catechol. The advantage of these new ligands is their high reactivity and excellent selectivity. The best results were obtained using ligand 7 to give the allylated catechol 24b from 23b in 90% ee and 91% yield within 4 hours.