Ferrocenyl ligands catalysis

Aminocarbonylation has also been applied to the synthesis of unsymmetrical ferrocene-1,1 -bis-carboxamides. Ferrocene-based chiral ligands are very useful in asymmetric catalysis, and enantiomerically pure ferrocenyl ligands can be obtained by optical resolution of unsymmetrically substituted ferrocenes. However, the synthesis of such unsymmetrical ferrocenes is not an easy task. The use of aminocarbonylation gave a solution to this challenge. For example, the Pd-catalyzed reaction of symmetrical ferrocenyl diiodide 144 with two different amines, morpholine and diethylamine (5 equiv. each) under 39.5 atm of CO, gave the desired unsymmetrically disubstituted ferrocene-biscarboxamide 145 in 85% yield (Equation (11)). ... 

Schwink, L. and Knochel, P. Enantioselective Preparation of C2-Symmetrical Ferrocenyl Ligands for Asymmetric Catalysis. Chem. Eur. J. 1998, 4, 950-968. 

Togni, A. (1996) Developing new chiral ferrocenyl ligands for asymmetric catalysis. A personal account. Chimia,... 

A. Togni in New Chiral Ferrocenyl Ligands for Asymmetric Catalysis in Metallocenes. Synthesis, Reactivity, Applications , eds. A. Togni and R. L. Halterman, Weinheim, 1998, Vol. 2, p. 685. 

Togni, A. Dorta, R. Kollner, C. Pioda, G. Some New Aspects of Asymmetric Catalysis with Chiral Ferrocenyl Ligands, Pure Appl. Chem. 1998, 70,1477-1485. 

For an outstanding example of a ferrocenyl ligand in asymmetric catalysis, see Blaser H-U (2002) Adv Syntb Catal 344 17 (and cited literature)... 

For a representative review, see Kagan, H.B., Diter, R, Gref, A., et al. (1996) Towards new ferrocenyl ligands for asymmetric catalysis. PureAppl. Chem., 68, 29-36, and references cited therein. 

The research group of Van Leeuwen has focused on catalysis at the core of a carbosilane dendrimer in an effort to be able to control stereoselectivity [10]. To this end, a ferrocenyl diphosphine backbone was functionalized with different generations of carbosilane dendrons producing a series of dendrimer phosphine ligands with an increasing steric demand (see 7 for an example, Scheme 6). In situ... 

The tremendous growth of the use of enantiomerically pure ligands in homogeneous asymmetric catalysis as led to significant efforts to immobilize the active catalysts in order to recycle them or prevent (or minimize) metal leaching into products. Both achiral and chiral ferrocenyl phosphines are among those catalysts that have been utilized in this context, and detailed descriptions of this research have appeared in a number of review articles. " " ... 

Allylic substitutions. Allylic substitution is still largely dependent on Pd-catalysis because of its efficiency and mechanistic understanding. Many new chiral ligands are tested for their asymmetric induction, including as diverse as the ferrocenyl S,P-hgands 23V24 and25. ... 

Colby EA, Jamison TF (2003) F-Chiral, monodentate ferrocenyl phosphines, novel ligands for asymmetric catalysis. J Org Chem 68 156-166... 

---