Chiral bidentate [N,S]-ferrocene ligands based on a thiazoline framework. Synthesis and use in palladium-catalyzed asymmetric allylic alkylation
Résumé
An efficient method to obtain chiral 1,2-disubstituted ferrocenyl ligands has been developed. The introduction of planar chirality was accomplished by using 2-thiazoline as an ortho-directing lithiation group, and moreover, these kinds of ligands possess a central chirality from the amino alcohol used in their synthesis. The X-ray analysis and DFT calculations confirmed the diastereoselectivity of ortho-lithiation and the configuration of the planar chirality. The ability of these new bidentate [N,S]-ferrocene ligands to act in Pd-catalyzed asymmetric allylic alkylation has also been demonstrated and compared with their oxazoline counterparts.