Synthesis, characterization and X-ray crystal structures of chiral ferrocene-containing β-diketones

Abstract

CCDC 922490, 922491, and 922492 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.International audienceThree new chiral ferrocene-containing β-diketones have been synthesized by reacting 1-ferrocenyl ethanol with the corresponding 1,3-diketone reagent MeCOCH2COR (R = Me, 4-C6H4OMe, Fc; Fc = (η5-C5H5)Fe(η5-C5H4)), using cerium(IV) ammonium nitrate (CAN) mediated C-C bond formation. These compounds identified as 3-(1-ferrocenylethyl)-pentane-2,4-dione (1), 1-(4-methoxyphenyl)-2-(1-ferrocenylethyl)-butane-1,3-dione (2), and 1-ferrocenyl-2-(1-ferrocenylethyl)-butane-1,3-dione (3), have been isolated as air and thermally stable microcrystalline solids in 79, 63 and 44% yields, respectively. Compounds 2 and 3 were formed in 63:37 and 88:12 diastereomeric ratios, respectively. They have been fully characterized by elemental analyses, FT-IR spectra, mass spectrometry, and their complete assignments have been conducted using 2D NMR experiments. In addition, their molecular identity and geometry have been confirmed by single-crystal X-ray diffraction, and both solution and solid state measurements have shown that the three complexes exist solely as their diketo tautomers

Molecular and Solid State Structure of the Doubly-Substituted B-Diketone 3,3'-Bis(ferrocenylmethyl)pentane-2,4-Dione#

“…The 1 H NMR spectrum of 1 in CDCl 3 solution shows only the keto tautomer with a signal integrating for 1 H at 3.75 ppm, assigned to the C-H proton, in agreement with our earlier work on 1,3-diketone-containing ethylferrocenes, 27 but in contrast to the 3:1 keto:enol ratio previously reported for 1. 29 Owing to its high symmetry, the 1 H NMR spectrum of 2 is remarkably simple and in accordance with the reported one; 29 it exhibits two sharp singlets at 2.10 (6 H) and 2.79 (4 H) ppm, attributable to the acetyl and methylene protons, respectively, and a broad resonance at 4.12 ppm assigned to the 18 protons of the two equivalent ferrocenyl moieties.…”

“…27,37 The lengths of the C-C in the connecting tetrahedral core, and of the C-C and C-Fe bonds in the ferrocene sandwiches (see Table 2) fall all within the range of standard values. 36,38 The bond angles at the central carbon C (12) Within the crystal structure of 2 there are several short intermolecular contacts.…”

“…26 Accordingly, we were able to isolate and structurally characterize three new chiral ferrocene-containing diketones starting from 1-ferrocenyl ethanol. 27 As a model reaction for this previous work, we tested the CAN-mediated C-C coupling reaction between achiral ferrocenyl methanol and acetylacetone. Herein, we wish to report on the outcome of this reaction and on the molecular and crystal structure of the doubly-substituted complex 3,3'-bis(ferrocenylmethyl)pentane-2,4-dione 2 (see Scheme 1 for formula).…”

A facile access to new diazepines derivatives: Spectral characterization and crystal structures of 7-(thiophene-2-yl)-5-(trifluoromethyl)-2,3-dihydro-1 H -1,4-diazepine and 2-thiophene-4-trifluoromethyl-1,5-benzodiazepine

“…Thus, it is attractive to obtain new heterocycles with potential biological properties from easy and minimum step reactions, involving inexpensive starting materials such as -diketones which can be functionalized in three different sites of the molecule. In the last few years, our groups have been interested in the synthesis of -diketones [5][6][7] as starting materials to be used in the preparation of heterocycles [8,9] and tridentate Schiff base ligands [10][11][12], via condensation with aliphatic M A N U S C R I P T…”

Octahedral bis(2-thenoyltrifluoroacetonato)-ethylenediamine Co(II), Ni(II) and Cu(II) complexes: Synthetic, structural, electrochemical, and theoretical studies

“…In the last few years, we have prepared different kinds of β-diketones [24][25][26] to be used as precursor for the preparation of several Schiff base ligands [25], metal complexes [27] and Schiff base oligomers [28]. Such condensation reactions proceed via the nucleophilic addition of the primary amine onto the carbonyl carbon giving a hemiaminal -C(OH)(NHR)-intermediate which, depending on the functional groups (R) and the experimental conditions evolves to the formation of a heterocyclic or a polydentate Schiff base compound [29].…”