35194-36-6Relevant articles and documents
Catalytic hydrogenation of sorbic acid using pyrazolyl palladium(II) and nickel(II) complexes as precatalysts
Darkwa, James,Kumar, Gopendra,Makhubela, Banothile C. E.,Muyaneza, Apollinaire,Olaoye, Oluwasegun E.,Oyetunji, Olayinka
, p. 50 - 56 (2021/12/09)
We have prepared several pyrazolyl palladium and nickel complexes ([(L1)PdCl2] (1), [(L2) PdCl2] (2), [(L3) PdCl2] (3), [(L1) NiBr2] (4), [(L2) NiBr2] (5) and [(L3) NiBr2] (6)) by reacting 3,5-dimethyl-1H-pyrazole (L1), 3,5-di-tert-butyl-1H-pyrazole (L2) and 5-ferrocenyl-1H-pyrazole(L3) with [PdCl2(NCMe)2] or [NiBr2(DME)] to afford mononuclear palladium and nickel complexes, respectively. These complexes were then investigated as pre-catalysts in the hydrogenation of 2,4-hexadienoic acid (sorbic acid). The active catalysts from these complexes demonstrate significant activities under mild experimental conditions. Additionally, the active catalysts show that the hydrogenation of sorbic acid proceeds in a sequential manner, where the less hindered C=C bond (4-hexenoic acid) is preferentially reduced over the more hindered C=C bond (2-hexenoic acid).
Iridium-catalyzed enantioselective hydroalkynylation via alkene isomerization
Zhang, Wen-Wen,Li, Bi-Jie
supporting information, (2021/05/10)
An iridium-catalyzed enantioselective alkynylation of methylene C–H bonds γ to the amide group is developed. The reaction proceeds through alkene isomerization followed by regioselective hydroalkynylation. This method provides rapid access to a wide range of stereodefined alkynylated compounds in good yields and good enantioselectivities.
Iridium-Catalyzed γ-Selective Hydroboration of γ-Substituted Allylic Amides
Zhao, Hongliang,Gao, Qian,Zhang, Yajuan,Zhang, Panke,Xu, Senmiao
supporting information, p. 2861 - 2866 (2020/04/02)
Reported here for the first time is the Ir-catalyzed γ-selective hydroboration of γ-substituted allylic amides under mild reaction conditions. A variety of functional groups could be compatible with reaction conditions, affording γ-branched amides in good yields with ≤97% γ-selectivity. We have also demonstrated that the obtained borylated products could be used in a series of C-O, C-F, C-Br, and C-C bond-forming reactions.
Highly active bidentate N-heterocyclic carbene/ruthenium complexes performing dehydrogenative coupling of alcohols and hydroxides in open air
Wang, Zhi-Qin,Tang, Xiao-Sheng,Yang, Zhao-Qi,Yu, Bao-Yi,Wang, Hua-Jing,Sang, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
supporting information, p. 8591 - 8594 (2019/07/25)
Eight bidentate NHC/Ru complexes, namely [Ru]-1-[Ru]-8, were designed and prepared. In particular, [Ru]-2 displayed extraordinary performance even in open air for the dehydrogenative coupling of alcohols and hydroxides. Notably, an unprecedentedly low catalyst loading of 250 ppm and the highest TON of 32 800 and TOF of 3200 until now were obtained.
Iridium-Catalyzed Distal Hydroboration of Aliphatic Internal Alkenes
Wang, Guangzhu,Liang, Xinyi,Chen, Lili,Gao, Qian,Wang, Jian-Guo,Zhang, Panke,Peng, Qian,Xu, Senmiao
, p. 8187 - 8191 (2019/05/27)
The regioselective hydroboration of aliphatic internal alkenes remains a great challenge. Reported herein is an iridium-catalyzed hydroboration of aliphatic internal alkenes, providing distal-borylated products in good to excellent yields with high regioselectivity (up to 99:1). We also demonstrate that the C?B bond of the distal-borylated product can be readily converted into other functional groups. DFT calculations indicate that the reaction proceeds through an unexpected IrIII/IrV cycle.
Iridium-Catalyzed Aerobic α,β-Dehydrogenation of γ,δ-Unsaturated Amides and Acids: Activation of Both α- And β-C-H bonds through an Allyl-Iridium Intermediate
Wang, Zhen,He, Zhiqi,Zhang, Linrui,Huang, Yong
supporting information, p. 735 - 740 (2018/01/26)
Direct aerobic α,β-dehydrogenation of γ, δ-unsaturated amides and acids using a simple iridium/copper relay catalysis system is described. We developed a new strategy that overcomes the challenging issue associated with the low α-acidity of amides and acids. Instead of α-C-H metalation, this reaction proceeds by β-C-H activation, which results in enhanced α-acidity. Conjugated dienamides and dienoic acids were synthesized in excellent yield with this reaction, which uses a simple reaction protocol. Mechanistic experiments suggest a catalyst resting state mechanism in which both α-C-H and β-C-H cleavage is accelerated.
Iron-Catalysed Selective Aerobic Oxidation of Alcohols to Carbonyl and Carboxylic Compounds
Lagerblom, Kalle,Wrigstedt, Pauli,Keskiv?li, Juha,Parviainen, Arno,Repo, Timo
, p. 1160 - 1165 (2016/11/23)
A method for aerobic alcohol oxidation catalysed by Fe(NO3)3/2,2’-bipyridine/TEMPO has allowed highly selective conversion of primary alcohols into either aldehydes or carboxylic acids in one-step. The oxidation of primary alcohols proceeded selectively to aldehydes, as TEMPO was present in the reaction. Nevertheless, the aldehydes were further oxidized into carboxylic acids as the reaction time was extended. Detailed investigation of the reaction suggested, that the deoxygenation of TEMPO into TMP enabled the auto-oxidation of aldehydes to carboxylic acids, which was initially inhibited in the presence of TEMPO. The procedure was also efficient in oxidation of secondary alcohols when TEMPO was replaced by the less sterically hindered ABNO.
Gold I-catalyzed highly diastereo- and enantioselective alkyne oxidation/cyclopropanation of 1,6-enynes
Qian, Deyun,Hu, Haoxiang,Liu, Feng,Tang, Bin,Ye, Weimin,Wang, Yidong,Zhang, Junliang
supporting information, p. 13751 - 13755 (2015/02/19)
A highly enantioselective oxidative cyclo-propanation of 1,6-enynes catalyzed by cationic AuI/ chiral phophoramidite complexes is presented. The new method provides convenient access to densely functionalized bicyclo[3.1.0]hexanes bearing three contiguous quaternary and tertiary stereogenic centers with high enantioselectivity (up to e.r. 98:2). Control experiments suggest that the quinoline moiety of the b-gold vinyloxyquinolinium intermediate in the reaction plays an important role in promoting good enantiose-lectivity through a transitional auxiliary effect in the transition state.
Selective isomerization-hydroformylation sequence: A strategy to valuable α-methyl-branched aldehydes from terminal olefins
Dydio, Pawel,Ploeger, Marten,Reek, Joost N. H.
, p. 2939 - 2942 (2014/01/06)
For the first time, an original selective isomerization-hydroformylation sequence to convert terminal olefins bearing an anionic moiety to α-methyl-branched aldehydes with unprecedented selectivities is reported. This opens up new synthetic avenues to these valuable building blocks from inexpensive and bioavailable substrates. The catalytic system involves a suitable selective monoisomerization catalyst and a selective supramolecular catalyst that preorganizes a substrate molecule prior to the hydroformylation reaction via hydrogen bonding. In principle, the strategy can be extended to other classes of substrates, providing suitable catalysts for the hydroformylation of internal alkenes.
Self-Protection: The Advantage of Radical Oligomeric Mixtures in Organic Synthesis
Yu, Hui,Li, Chaozhong
, p. 142 - 145 (2007/10/03)
Atom-transfer radical oligomers of allyl iodoacetates were converted to 4-pentenoic acids upon treatment with zinc. Reactions of the radical oligomers of various ω-alkenyl iodoacetates with Grignard reagents afforded the corresponding substituted tetrahydrofuran derivatives. These results indicated that radical oligomeric mixtures not only serve as versatile intermediates in organic synthesis, but also exhibit unique advantages in that the oligomeric mixtures are self-protected and the deoligomerization functions as the simultaneous deprotection.
