1481-90-9Relevant articles and documents
Nickel-catalyzed reductive deoxygenation of diverse C-O bond-bearing functional groups
Cook, Adam,MacLean, Haydn,St. Onge, Piers,Newman, Stephen G.
, p. 13337 - 13347 (2021/11/20)
We report a catalytic method for the direct deoxygenation of various C-O bond-containing functional groups. Using a Ni(II) pre-catalyst and silane reducing agent, alcohols, epoxides, and ethers are reduced to the corresponding alkane. Unsaturated species including aldehydes and ketones are also deoxygenated via initial formation of an intermediate silylated alcohol. The reaction is chemoselective for C(sp3)-O bonds, leaving amines, anilines, aryl ethers, alkenes, and nitrogen-containing heterocycles untouched. Applications toward catalytic deuteration, benzyl ether deprotection, and the valorization of biomass-derived feedstocks demonstrate some of the practical aspects of this methodology.
Solvent-Controlled Hydrogenation of 2’-Hydroxychalcones: A Simple Solution to the Total Synthesis of Bussealins
Soto, Martín,Soengas, Raquel G.,Rodríguez-Solla, Humberto
, p. 5422 - 5431 (2020/10/06)
A solvent-controlled hydrogenation of 2’-hydroxychalcones to selectively obtain different hydrogenation products is herein reported. Thus, hydrogenation of 2’-hydroxychalcones using EtOH as solvent provided the corresponding 1,3-diarylpropanes in excellent yields. On the contrary, when the hydrogenation was performed in DCM, the corresponding dihydrochalcones were isolated. Switching the reaction solvent to n-BuOH/H2O (1:1), afforded 1,3-diarylpropanols from moderate to good yields. The methodology here reported offers a straightforward, simple and cost-effective method for the preparation of a wide variety of 2’-hydroxy-1,3-diarylpropanes derivatives, and was also applied to the preparation of natural Bussealins C and D. (Figure presented.).
Scope and Mechanistic Analysis for Chemoselective Hydrogenolysis of Carbonyl Compounds Catalyzed by a Cationic Ruthenium Hydride Complex with a Tunable Phenol Ligand
Kalutharage, Nishantha,Yi, Chae S.
supporting information, p. 11105 - 11114 (2015/09/15)
A cationic ruthenium hydride complex, [(C6H6)(PCy3)(CO)RuH]+BF4- (1), with a phenol ligand was found to exhibit high catalytic activity for the hydrogenolysis of carbonyl compounds to yield the corresponding aliphatic products. The catalytic method showed exceptionally high chemoselectivity toward the carbonyl reduction over alkene hydrogenation. Kinetic and spectroscopic studies revealed a strong electronic influence of the phenol ligand on the catalyst activity. The Hammett plot of the hydrogenolysis of 4-methoxyacetophenone displayed two opposite linear slopes for the catalytic system 1/p-X-C6H4OH (ρ = -3.3 for X = OMe, t-Bu, Et, and Me; ρ = +1.5 for X = F, Cl, and CF3). A normal deuterium isotope effect was observed for the hydrogenolysis reaction catalyzed by 1/p-X-C6H4OH with an electron-releasing group (kH/kD = 1.7-2.5; X = OMe, Et), whereas an inverse isotope effect was measured for 1/p-X-C6H4OH with an electron-withdrawing group (kH/kD = 0.6-0.7; X = Cl, CF3). The empirical rate law was determined from the hydrogenolysis of 4-methoxyacetophenone: rate = kobsd[Ru][ketone][H2]-1 for the reaction catalyzed by 1/p-OMe-C6H4OH, and rate = kobsd[Ru][ketone][H2]0 for the reaction catalyzed by 1/p-CF3-C6H4OH. Catalytically relevant dinuclear ruthenium hydride and hydroxo complexes were synthesized, and their structures were established by X-ray crystallography. Two distinct mechanistic pathways are presented for the hydrogenolysis reaction on the basis of these kinetic and spectroscopic data. (Chemical Equation Presented).
