67077-43-4Relevant academic research and scientific papers
Reductive alkylation of thioamides with Grignard reagents in the presence of Ti(O i Pr)4: Insight and extension
Hermant, Fabien,Urbaska, Ewelina,Seizilles De Mazancourt, Sarah,Maubert, Thomas,Nicolas, Emmanuel,Six, Yvan
supporting information, p. 5643 - 5653 (2015/02/19)
The reductive alkylation of thioamides by Grignard reagents in the presence of Ti(OiPr)4 is the subject of a study involving 20 different substrates. The influence of various parameters has been evaluated, showing notably that the yields of this moderately efficient process can be improved in several cases by applying a slow addition of the Grignard reagent. The results presented in this contribution also provide new insight into the reactivity of the proposed key intermediates, namely, a metalated iminium species and, ultimately, an α-metalated amine. Interestingly, by control of the temperature and the amount of Grignard reagent engaged, the reaction can be directed toward the selective formation of the former titanium intermediate complex. This represents an extension of the original method, allowing the synthesis of various previously inaccessible substituted amines by subsequent addition of a nucleophilic reagent. This role can be played not only by organomagnesium compounds but also by alkyllithium reagents, alkyltitanium(IV) complexes, and lithium aluminum hydride. The properties of the α-metalated amine final intermediate have also been explored, demonstrating that this complex is a poor nucleophile but can act as a radical precursor, which is especially evidenced when the resulting radical species are stabilized. Overall, this chemistry thus proves unexpectedly rich and can plausibly lay the basis for the development of new applications in the future.
Aminocyclopropanes as precursors of endoperoxides with antimalarial activity
Madelaine, Claire,Buriez, Olivier,Crousse, Benoit,Florent, Isabelle,Grellier, Philippe,Retailleau, Pascal,Six, Yvan
supporting information; experimental part, p. 5591 - 5601 (2011/02/18)
This contribution describes the synthesis of several novel bicyclic α-amino endoperoxides, including CF3-substituted compounds, prepared by the aerobic electrochemical oxidation of a family of bicyclic aminocyclopropanes. These, in turn, are re
New selectivities from old catalysts. Occlusion of Grubbs' catalysts in PDMS to change their reactions
Brett Runge,Mwangi, Martin T.,Bowden, Ned B.
, p. 5278 - 5288 (2007/10/03)
This article describes new selectivities for Grubbs' first and second generation catalysts when occluded in a hydrophobic matrix of polydimethylsiloxane (PDMS). Occlusion of catalysts in mm-sized slabs of PDMS is accomplished by swelling with methylene chloride then removing the solvent under vacuum. The catalysts are homogenously dissolved in PDMS yet remain catalytically active. Many substrates that react by olefin metathesis with Grubbs' catalysts freely dissolved in methylene chloride also react by olefin isomerization with occluded catalysts. Eleven examples of substrates that exhibit dual reactivity by undergoing olefin isomerization with occluded catalysts and olefin metathesis with catalysts dissolved in methylene chloride are reported. Most of these substrates have olefins with allylic phosphine oxides, carbonyls, or ethers. Control experiments demonstrate that isomerization is occurring in the solvent by decomposition of the catalyst from a ruthenium carbene to a proposed ruthenium hydride. This work was extended by heating occluded Grubbs' first generation catalyst to 100 °C in 90% MeOH in H2O in the presence of various alkenes to transform the Grubbs' catalyst into an isomerization catalyst for unfunctionalized olefins. This work demonstrates that occlusion of organometallic catalysts in PDMS has important implications for their reactions and can be used as a method to control which reactions they catalyze.
