3937-48-2Relevant academic research and scientific papers
Hydrogenation of alkenes via cooperative hydrogen atom transfer
Kattamuri, Padmanabha V.,West, Julian G.
supporting information, p. 19316 - 19326 (2020/11/13)
Radical hydrogenation via hydrogen atom transfer (HAT) to alkenes is an increasingly important transformation for the formation of thermodynamic alkane isomers. Current single-catalyst methods require stoichiometric oxidant in addition to hydride (H-) source to function. Here we report a new approach to radical hydrogenation: cooperative hydrogen atom transfer (cHAT), where each hydrogen atom donated to the alkene arrives from a different catalyst. Further, these hydrogen atom (H?) equivalents are generated from complementary hydrogen atom precursors, with each alkane requiring one hydride (H-) and one proton (H+) equivalent and no added oxidants. Preliminary mechanistic study supports this reaction manifold and shows the intersection of metal-catalyzed HAT and thiol radical trapping HAT catalytic cycles to be essential for effective catalysis. Together, this unique catalyst system allows us to reduce a variety of unactivated alkene substrates to their respective alkanes in high yields and diastereoselectivities and introduces a new approach to radical hydrogenation.
IL-17 Ligands And Uses Thereof
-
Paragraph 1001-1002, (2020/08/20)
Provided herein are novel ligands and pharmaceutical compositions thereof which modulate IL-17A. Also provided are methods for preparing the IL-17A modulators. Such compounds may be useful in the treatment and/or prevention of, for example, inflammation, cancer or autoimmune disease.
Simple, chemoselective hydrogenation with thermodynamic stereocontrol
Iwasaki, Kotaro,Wan, Kanny K.,Oppedisano, Alberto,Crossley, Steven W. M.,Shenvi, Ryan A.
supporting information, p. 1300 - 1303 (2014/02/14)
Few methods permit the hydrogenation of alkenes to a thermodynamically favored configuration when steric effects dictate the alternative trajectory of hydrogen delivery. Dissolving metal reduction achieves this control, but with extremely low functional group tolerance. Here we demonstrate a catalytic hydrogenation of alkenes that affords the thermodynamic alkane products with remarkably broad functional group compatibility and rapid reaction rates at standard temperature and pressure.
Bis(phosphine)cobalt dialkyl complexes for directed catalytic alkene hydrogenation
Friedfeld, Max R.,Margulieux, Grant W.,Schaefer, Brian A.,Chirik, Paul J.
supporting information, p. 13178 - 13181 (2015/03/30)
Planar, low-spin cobalt(II) dialkyl complexes bearing bidentate phosphine ligands, (P - P)Co-(CH2SiMe3)2, are active for the hydrogenation of geminal and 1,2-disubstituted alkenes. Hydrogenation of more hindered internal and endocyclic trisubstituted alkenes was achieved through hydroxyl group activation, an approach that also enables directed hydrogenations to yield contrasteric isomers of cyclic alkanes.
Axial and equatorial cyclohexylacyl and tetrahydropyranyl-2-acyl radicals. An experimental and theoretical study
DiLabio, Gino A.,Ingold, Keith U.,Roydhouse, Mark D.,Walton, John C.
, p. 4319 - 4322 (2007/10/03)
(Chemical Equation Presented) Axial and equatorial cyclohexylacyl and tetrahydropyranyl-2-acyl radicals gave distinct EPR spectra thanks to surprisingly large β-hydrogen atom hyperfine splittings that enabled them to be characterized and monitored. DFT computations indicated that the axial species (X = CH2) had a higher barrier to rotation about the (O)Cα-Cα bond. The computed difference ΔH° for the axial and equatorial radicals (R = H, X = CH2) was 0.8 kcal mol -1.
Stereoselective Metal Catalysed Hydroboration of 4-Substituted 1-Methylidenecyclohexanes
Hou, Xue-Long,Xie, Quan-Cheng,Dai, Li-Xin
, p. 2665 - 2678 (2007/10/03)
Rhodium catalysed hydroboration of 4-substituted 1-methylidenecyclohexanes gives cis-hydroboration products with high stereoselectivity.The effects influencing the stereochemistry are discussed.
Directing Effects in Homogeneous Hydrogenation with PF6
Crabtree, Robert H.,Davis, Mark W.
, p. 2655 - 2661 (2007/10/02)
The presence of a ligating group, e.g., OH, CO2Me, C=O, or OMe, on an olefinic substrate is shown to direct the attack of the hydrogenation catalyst PF6/H2/CH2Cl2 from the face of the molecule containing the directing group.Isomerization is a minor side reaction in the cases studied.The origin of this effect is discussed and a model intermediate isolated.
