RESUMO
A simple protocol has been developed for the chemoselective synthesis of ferrocene-containing Rauhut-Currier adducts from 1-ferrocenyl-2-nitroethene and vinyl ketones using 20 mol% of triphenylphosphine. Multifunctional ferrocene derivatives were obtained in moderate to high yields (51-92%) by the coupling between the α-position of vinyl ketones and the ß-position of the nitroalkene. The study of the Rauhut-Currier reaction under the described conditions showed that the strong electron-donating group at the ß-position of nitroalkenes plays a significant role in the reaction outcome due to prevention of polymerization and stabilization of the zwitterionic intermediate. Additionally, a preparative synthesis of 4-ferrocenyl-3-methylene-5-nitropentan-2-one was carried out and its synthetic transformations showed easy conversion to other useful building blocks.
RESUMO
The synthesis of a series of methyl 2-alkyl-5-aryl-4-ferrocenoylpyrrolidine-2-carboxylates has been achieved by [3 + 2] dipolar cycloaddition of azomethine ylides to acryloylferrocene. The electrochemical properties of novel products were examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). These techniques revealed the quasi-reversible one-electron oxidation process. The DNA-binding capacity of all the products was also studied using CV and DPV, and significant interactions between synthesized compounds and nucleic acid, mostly of the electrostatic type, were disclosed. DFT calculations and molecular docking tests were carried out to gain a more exhaustive insight into the interactions of the obtained products with nucleic acid. A detailed characterization of the new compounds was performed by IR, NMR and elemental analyses, followed by single-crystal X-ray diffraction experiments for two representatives.
