Formation and structural characterization of amino-substituted [3]ferrocenophanes derived from intramolecular Mannich-type coupling reactions at the metallocene framework

Preparation of Optically Active α‐Amino[3]ferrocenophanes − Building Blocks for Chelate Ligands in Asymmetric Catalysis

“…The major product of this surprisingly high trans-selective reduction (trans-5) was obtained in its pure Scheme 1 Preparation of Optically Active α-Amino[3]ferrocenophanes FULL PAPER form after recrystallization. [10] The product rac-trans-6 was then converted into a series of chelate ligands, especially to the bis(phosphanyl) [3]ferrocenophane rac-3, which was used to generate a very active Pd-based catalyst for the alternating CO/ethene copolymerization. [11,12] So far our chemistry leading to 3 and a number of related compounds was carried out at the stage of the racemic compounds which were also used in the first catalytic test reactions.…”

“…The observation that the catalytic hydrogenation of the doubly unsaturated enamine 5 in the presence of palladium on charcoal proceeded predominantly with an overall trans stereochemistry [10] indicated a stepwise hydrogenation pathway with an active involvement of the amino group at the surface of the catalyst. Therefore, it needed to be tested whether the attachment of a chiral amino auxiliary would lead to a considerable asymmetric induction.…”

“…The C8 methylene group is characteristically placed outside the C1ϪC6/C9ϪC13 plane, so that the substituents at the saturated C3 bridge [C1ϪC6 1.515(3), C6ϪC8 1.546(4), C8ϪC9 1.537(3), C9ϪC10 1.502(3) Å ; C1ϪC6ϪC8 112.6(2), C6ϪC8ϪC9 112.5(2), C8ϪC9ϪC10 113.9(2)°] have become oriented pseudo-axially (CH 3 at C6) or pseudo-equatorially (NMe 2 at C9). [10] The corresponding dihedral angles of the [3]ferrocenophane framework amount to 63.8(3)°(C1ϪC6ϪC8ϪC9) and Ϫ79.0(2)°(C6ϪC8ϪC9ϪC10). The respective substituent positions at this framework are characterized by dihedral angles of Ϫ63.6(3)°(C7ϪC6ϪC8ϪC9) and 153.1(2)°( C6ϪC8ϪC9ϪN1).…”

Side‐Chain Effects on the 1‐(Bis‐aryl‐methylidene)‐[3]ferrocenophane Skeleton: Antiproliferative Activity against TNBC Cancer Cells and Comparison with the Acyclic Ferrocifen Series

“…The geometry of the [3]ferrocenophane moiety in 26 closely resembles those reported previously. [19,22] The system crystallizes with two independent molecules in the unit cell. As expected, the threecarbon bridge between the two cyclopentadienyl rings is too short for them to maintain their coplanarity and the dihedral angles between the ring planes in the independent molecules are 9.5 and 10°.…”

The Mannich Route to Amino-Functionalized [3]Ferrocenophanes

“…In this case we isolated the [3]ferrocenophane derivative 12a in >80% yield (see Scheme 4.5). 19,20 Several derivatives of the [3]ferrocenophane amine systems that were prepared by this "direct" method were characterized by X-ray diffraction, among them the "parent" compound 12a 19 (see Fig. 4.2).…”