Cyclic Ether Induced Asymmetric Cyclopalladation:  Synthesis and Structural Characterization of Enantiopure Bis(μ-acetato)-Bridged Dimers of Planar Chiral Cyclopalladated Ferrocenylimines and Their Derivatives

Abstract

Enantiopure bis(μ-acetato)-bridged planar chiral cyclopalladated products (R = H, Me) have been obtained by asymmetric cyclopalladation of the corresponding chiral ferrocenylimines with palladium(II) acetate and sodium acetate in methanol at room temperature with a high level of diastereoselectivity (product ratio syn-(+)-(R p,R,R,R p):syn-(−)-(S p,R,R,S p) ≈ syn-(−)-(S p,S,S,S p):syn-(+)-(R p,S,S,R p) ≈ 9:1). One or both acetato groups can be readily substituted by other anionic ligands to yield novel mixed-bridge or bis(μ-anion)-bridged planar chiral dimers of ferrocene derivatives. The first cis-type syn-(R p,S p) cyclopalladated dimer of ferrocenylimine has been obtained. The diphenylacetylene insertion reaction of a variety of anion-bridged planar chiral dimeric cyclopalladated derivatives of ferrocene has also been investigated. The absolute configurations of bis(μ-acetato)-, bis(μ-halogeno)-, (μ-1κS:2κN)-(μ-1κN:2κS)-thiocyanato-, and (μ-1κO:2κN)-(μ-1κN:2κO)-nitrito-bridged planar chiral dimers and bis(diphenylacetylene) insertion products have been elucidated by single-crystal X-ray analysis.

Reactivity of cyclopalladated compounds derived from biphenyl-2-ylamine towards carbon monoxide, tbutyl isocyanide and alkynes

“…Thus, these compounds adopt the structure found in most organopalladium compounds derived from the insertion of two alkyne molecules into the C-Pd r bonds of five-and six-membered cyclopalladated compounds, in which the resulting butadienyl fragment presents a trans-cis configuration and is g 2 -j 1 coordinated to the palladium(II) centre [16]. Distances and angles around the palladium(II) centre in compounds 5 and 6 were within the normal range for this kind of organopalladium compound [20,24,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. As expected (i) the carbon-carbon distances of the alkene units coordinated g 2 to the palladium(II) centres were larger than the carbon-carbon distances of the alkene units coordinated j 1 to the palladium(II) centres À1.409(3) Å and 1.325(3) Å for compound 5 and 1.387(6) Å and 1.376 (7) Å for compound 6 -and (ii) the alkene units coordinated g 2 to the palladium(II) centre were no longer planar -the dihedral angles C14-C13-C20-C21 for compound 5 and C14-C13-C16-C17 for compound 6 were 152.1(2)°a nd 164.5(4)°, respectively.…”

Non-racemic (scalemic) planar-chiral five-membered metallacycles: routes, means, and pitfalls in their synthesis and characterization

“…ð5Þ With chiral imines. The ortho-metallation of ferrocenyl imines prepared from racemic ferrocene aldehyde, acetylferrocene or benzoylferrocene and enantioenriched amines such as (2)-cis-myrtanylamine (29 and 30, Chart 1), 42 (R)-1-naphthylethylamine (31, Chart 1), 43 cyclic hydrazines (32-35, Chart 1), [44][45][46] (R) and (S)-tetrahydrofurfurylamine (36-37and 38-39, Chart 1), 47 (S)-1-cyclohexyl-ethylamine 48 (40, Chart 1), (S) and (R)-1-phenyl-ethylamine 49…”

Fabrication of Redox‐ and pH‐Sensitive Self‐Assembled Nano‐Micelles with Pegylated β‐Cyclodextrin for Codelivery of Doxorubicin and Cyclopalladated Ferrocene

“…Compounds C1 and C2 were synthesized in a previously reported way. [26] In brief, C1 was obtained by a condensation reaction between ferrocenecarboxaldehyde and (S)-(+)-tetrahydrofurfurylamine in dry toluene. C1 was mixed with NaPdCl 4 and NaOAc in a 1 : 1 : 1 molar ratio in dry methanol at room temperature for 24 h to produce C2.…”