949004-85-7Relevant academic research and scientific papers
Asymmetric Catalysis with Iron-Salen Complexes
Shaw, Subrata,White, James D.
, p. 2768 - 2780 (2016/08/31)
Iron(III)-salen complexes based on a chiral cis-2,5-diaminobicyclo[2.2.2]octane scaffold are used as catalysts for a variety of stereo selective reactions. High enantio- and diastereoselectivities can be achieved with these catalysts in sulfa-Michael conjugate addition to acyclic α,β-unsaturated ketones, in regioselective δ-addition of thiols to acyclic α,β,γ,δ-unsaturated ketones, and in Conia-ene carbocyclization of alkynyl-substituted β-dicarbonyl compounds. The use of these chiral iron-salen complexes as catalysts provides a new method for conducting these three important reactions under environmentally sustainable conditions.
A new iron(III)-salen catalyst for enantioselective Conia-ene carbocyclization
Shaw, Subrata,White, James. D.
supporting information, p. 13578 - 13581 (2015/02/05)
A chiral iron(III)-salen complex based on a cis-2,5-diaminobicyclo[2.2.2]octane scaffold catalyzes asymmetric Conia-ene-type cyclization of α-functionalized ketones containing an unactivated terminal alkyne and produces an exo-methylenecycloalkane possess
Persistent hydrogen-bonded and non-hydrogen-bonded phenoxyl radicals
Wanke, Riccardo,Benisvy, Laurent,Kuznetsov, Maxim L.,Guedes Da Silva, M. Fatima C.,Pombeiro, Armando J. L.
, p. 11882 - 11892 (2011/11/29)
The production of stable phenoxyl radicals is undoubtedly a synthetic chemical challenge. Yet it is a useful way to gain information on the properties of the biological tyrosyl radicals. Recently, several persistent phenoxyl radicals have been reported, but only limited synthetic variations could be achieved. Herein, we show that the amide-o-substituted phenoxyl radical (i.e. with a salicylamide backbone) can be synthesised in a stable manner, thereby permitting easy synthetic modifications to be made through the amide bond. To study the effect of H-bonding on the properties of the phenolate/phenoxyl radical redox couple, simple H-bonded and non-H-bonded o,p-tBu-protected salicylamidate compounds have been prepared. Their redox properties were examined by cyclic voltammetry and showed a fully reversible one-electron oxidation process to the corresponding phenoxyl radical species. Remarkably, the redox potential appears to be correlated, at least partially, with H-bond strength, as relatively large differences (ca. 300 mV) in the redox potential between H-bonded and non-H-bonded phenolate salts are observed. The corresponding phenoxyl radicals produced electrochemically are persistent at room temperature for at least an hour; their UV/Vis and EPR characterisation is consistent with that of phenoxyl radicals, which makes them excellent models of biological tyrosyl radicals. The analyses of the experimental data coupled with theoretical calculations indicate that both the deviation from planarity of the amide function and intramolecular H-bonding influence the oxidation potential of the phenolate. The latter H-bonding effect appears to be predominantly exerted on the phenolate and not (or only a little) on the phenoxyl radical. Thus, in these systems the H-bonding energy involved in the phenoxyl radical appears to be relatively small.
Convenient and efficient method for the obtainment of ketones from highly hindered aromatic N,N-dimethyl-amides
Jimenez, Claudio A.,Belmar, Julio B.
, p. 2391 - 2397 (2008/02/10)
A simple and efficient procedure to synthesize highly hindered alkyl aryl ketones that involves the coupling of N,N-dimethyl-3,5-di-tert-butylsalicylamide with organolithium compounds is described. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the procedure. Copyright Taylor & Francis Group, LLC.
