221527-96-4Relevant academic research and scientific papers
MOESSBAUER STUDIES ON FERROCENE COMPLEXES. X. STERIC AND POLAR FACTORS IN FERROCENYL KETONES AND CARBENIUM IONS
Neshvad, G.,Roberts, R.M.G.,Silver, J.
, p. 319 - 330 (1984)
A series of new ferrocenyl alcohols of the types and FcCH(OH)R where R=1-adamantyl, 9-anthracyl and mesityl have been synthesised.The 1H NMR spectra of these carbenium ions derived from these alcohols have been measured and discussed, together with those of the ketone precursors in CF3CO2H.Moessbauer spectra were obtained for the above derivatives in frozen solid solution in CF3CO2H.For the protonated ketones only small differences in quadrupole splitting (QS) were observed as the structure of the aryl or alkyl groups was varied, all having QS values of 0.23-0.36 mm s-1 lower than that of ferrocene.For the aryl carbenium ions the enhanced QS correlated reasonably well with Hammett ?+ values (r=0.953, 7 points).No systematic trends in QS were observed for the o, m and p series of substituents.The more sterically hindered carbenium ions show a significant lowering of QS due to the Cp rings twisting out of the carbenium ion sp2 plane.In the case of the anthracyl derivative, no appreciable change in QS occurred on forming the carbenium ion indicative of stabilisation of the ion by the anthracyl rather than the ferrocenyl moiety.The different modes of stabilisation of the protonated ketones and the carbenium ions are discussed.
Activation and Substitution of 1-Ferrocenylalkylamines with Allenones: Application to Three-Component Synthesis of 4-(1-Ferrocenylalkyl)pyrazoles
Chen, Zhixiong,Han, Lu,Tian, Shi-Kai
supporting information, p. 5852 - 5855 (2017/11/10)
A one-pot, two-step three-component synthesis of 4-(1-ferrocenylalkyl)pyrazoles has been developed involving activation and substitution of 1-ferrocenylalkylamines with allenones under mild conditions. A range of 1-ferrocenylalkylamines reacted with allenones in the presence of dipicolinic acid at room temperature without extrusion of air and moisture, and the resulting crude products were treated with hydrazine to afford structurally diverse 4-(1-ferrocenylalkyl)pyrazoles in moderate to good yields. Moreover, the three-component reaction was successfully extended to an enantioenriched α-ferrocenylbenzylamine with complete retention of configuration.
Ruthenium-Catalyzed Enantioselective Hydrogenation of Ferrocenyl Ketones: A Synthetic Method for Chiral Ferrocenyl Alcohols
Lu, Bin,Wang, Qun,Zhao, Mengmeng,Xie, Xiaomin,Zhang, Zhaoguo
, p. 9563 - 9569 (2015/10/12)
Highly effective asymmetric hydrogenation of various ferrocenyl ketones, including aliphatic ferrocenyl ketones as well as the more challenging aryl ferrocenyl ketones, was realized in the presence of a Ru/diphosphine/diamine bifunctional catalytic system. Excellent enantioselectivities (up to 99.8% ee) and activities (S/C = 5000) could be obtained. These asymmetric hydrogenations provided a convenient and efficient synthetic method for chiral ferrocenyl alcohols, which are key intermediates for a variety of chiral ferrocenyl ligands and resolving reagents.
