64273-11-6Relevant 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.
Specific Inhibition of the Hydrogenolysis of Benzylic C?O Bonds Using Palladium Nanoparticles Supported on Nitrogen-Doped Carbon Nanofibers
Motoyama, Yukihiro,Morii, Koshi,Ishizuka, Shoya,Inomoto, Sou,Zhang, Zhenzhong,Yoon, Seong-Ho
, p. 505 - 509 (2018/02/15)
Palladium nanoparticles supported on 5 %-nitrogen-doped, herringbone-type carbon nanofibers (Pd/N-CNF-H), which are prepared by thermally decomposing [Pd2(dba)3?CHCl3] (dba=dibenzylideneacetone) in toluene in the presence of N-CNF-H, were found to be an efficient catalyst for the chemoselective hydrogenation of alkenyl and nitro moieties in benzyl-protected alcohols and carboxylic acid derivatives with high turnover frequencies: the hydrogenation reactions of these functional groups proceeded smoothly even at ambient temperature under atmospheric H2 pressure, and the benzyl protecting groups in the molecules remained intact. Moreover, the recovered Pd/N-CNF-H catalyst could be reused without loss of its catalytic activity or chemoselectivity. The Pd/N-CNF-H catalyst also acted as an effective hydrogenation catalyst for the reduction of aromatic ketones to the corresponding benzyl alcohol derivatives with good to high product selectivity.
Palladium nanoparticles obtained from palladium salts and tributylamine in molten tetrabutylammonium bromide: Their use for hydrogenolysis-free hydrogenation of olefins
Le Bras, Jean,Mukherjee, Deb Kumar,Gonzalez, Sara,Tristany, Mar,Ganchegui, Benjamin,Moreno-Manas, Marcial,Pleixats, Roser,Henin, Francoise,Muzart, Jacques
, p. 1550 - 1553 (2007/10/03)
Carbon-carbon double bonds have been selectively hydrogenated at room temperature in the presence of benzyloxy groups using an atmospheric pressure of hydrogen, toluene or [bmim]PF6 as the solvent and palladium nanoparticles stabilized with tetrabutylammonium bromide. The system [bmim]PF6/palladium nanoparticles can be recycled without noticeable decrease of activity.
Process for the preparation of carboxylic benzyl esters
-
, (2008/06/13)
Carboxylic benzyl esters can be prepared by reacting benzyl chloride with carboxylic acids in the presence of one or more quaternary ammonium carboxylates as catalyst.
Oxidative Cleavage of Mono-, Di-, and Trisubstituted Olefins to Methyl Esters through Ozonolysis in Methanolic NaOH
Marshall, James A.,Garofalo, Albert W.
, p. 3675 - 3680 (2007/10/02)
The ozonolysis of alkenes in methanolic NaOH or NaOMe with CH2Cl2 as cosolvent leads directly to methyl esters.The procedure has been used to prepare various α-, β-, and ω-alkoxy esters, acyloxy esters, and α- and β-N-acyl and N-sulfonyl esters from appropriate unsaturated ethers, esters and amides.Other examples include the formation of dimethyl octanedioate from cyclooctene (75percent yield), dimethyl nonanedioate and methyl nonaoate from methyl oleate (77 and 78percent, respectively), and tetradecanoic acid γ-lactone from 2-methyl-2-hexadecen-6-ol (80percent yield).
