Asymmetric Hydrogenation Catalyzed by Bifunctional Knolker Type Complexes

Background: This review focuses on the recent advances in the asymmetric hydrogenation of pro-chiral C=O and C=N double bonds catalyzed by iron-catalysts based on chiral and achiral Knolker type complexes. Method: The bifunctional nature of such complexes made possible the development of two strategies to achieve asymmetric hydrogenation. The first approach is based on the design of chirally modified Fe-complexes, while the second one relies on the cooperative catalysis of an achiral iron-complex and a chiral additive. Forty-two papers are included in the review.