112-88-9Relevant articles and documents
Probing the mechanism of cyanobacterial aldehyde decarbonylase using a cyclopropyl aldehyde
Paul, Bishwajit,Das, Debasis,Ellington, Benjamin,Marsh, E. Neil G.
, p. 5234 - 5237 (2013)
Cyanobacterial aldehyde decarbonylase (cAD) is a non-heme diiron oxygenase that catalyzes the conversion of fatty aldehydes to alkanes and formate. The mechanism of this chemically unusual reaction is poorly understood. We have investigated the mechanism of C1-C2 bond cleavage by cAD using a fatty aldehyde that incorporates a cyclopropyl group, which can act as a radical clock. When reacted with cAD, the cyclopropyl aldehyde produces 1-octadecene as the rearranged product, providing evidence for a radical mechanism for C-C bond scission. In an alternate pathway, the cyclopropyl aldehyde acts as a mechanism-based irreversible inhibitor of cAD through covalent binding of the alkyl chain to the enzyme.
Construction of bifunctional co/h-zsm-5 catalysts for the hydrodeoxygenation of stearic acid to diesel-range alkanes
Wu, Guangjun,Zhang, Nan,Dai, Weili,Guan, Naijia,Li, Landong
, p. , 2179 (2018)
Bifunctional Co/H-ZSM-5 zeolites were prepared by a surface organometallic chemistry grafting route, namely, by the stoichiometric reaction between cobaltocene and the Br?nsted acid sites in zeolites. The catalyst was applied to a model reaction of the catalytic hydrodeoxygenation of stearic acid (SA). The cobalt species existed in the form of isolated Co2 + ions at the exchange positions after grafting, transformed to CoO species on the surface of the zeolite, stabilized inside the zeolite channels upon calcination in air, and finally reduced by hydrogen to homogeneous clusters of metallic cobalt species approximately 1.5 nm in size. During this process, the Br?nsted acid sites of the H-ZSM-5 zeolites were preserved with a slight-ly reduced acid strength. The as-prepared bifunctional catalyst exhibited an approximately 16 times higher activity for the hydrodeoxygenation of SA (2.11 gSA gcat1 h1) than the reference catalyst (0.13 gSA gcat1 h1) prepared by solid-state ion exchange and a high C18 /C17 ratio of approximately 24. The remarkable hydrodeoxygenation performance of the bifunctional Co/H-ZSM-5 was owed to the effective synergy between the uniformed metallic cobalt clusters and the Br?nsted acid sites in H-ZSM-5. The simplified reaction network and kinetics of the SA hydrodeoxygenation catalyzed by the as-prepared bifunctional Co/H-ZSM-5 zeolites were also investigated.
Molybdenum carbide-catalyzed conversion of renewable oils into diesel-like hydrocarbons
Han, Junxing,Duan, Jinzhao,Chen, Ping,Lou, Hui,Zheng, Xiaoming
, p. 2577 - 2583 (2011)
In the paper, we report for the first time that the conversion of renewable oils into diesel-like hydrocarbon mixtures can be realized on molybdenum carbides with high activity and selectivity. The molybdenum carbide catalyst exhibited much better resistance to leaching than noble metals and could be reused consecutively for sixteen times without deactivation. Mechanism investigations indicated that molybdenum carbide and palladium showed different reaction selectivities and it was speculated that the level of difficulty in acyl-to-alkyl rearrangement of surface acyl intermediates on molybdenum carbide and palladium resulted in the different product selectivity. Copyright
Direct Synthesis of Polysubstituted Aldehydes via Visible-Light Catalysis
Wu, Fengjin,Wang, Leifeng,Chen, Jiean,Nicewicz, David A.,Huang, Yong
, p. 2174 - 2178 (2018)
Aldehydes are among the most versatile functional groups for synthetic chemistry. However, access to polysubstituted alkyl aldehydes is very limited and requires lengthy synthetic routes that involve multiple-step functional-group conversion. This paper reports a one-step synthesis of polysubstituted aldehydes from readily available olefin substrates using visible-light photoredox catalysis. Despite a number of competing reaction pathways, commercial styrenes react with vinyl ethers selectively in the presence of an acridinium salt photooxidant and a disulfide hydrogen-atom-transfer catalyst under blue LED irradiation. Alkyl aldehydes with different substitution patterns are prepared in good yields. This strategy can be applied to structurally sophisticated substrates.
Synthesis of 2,2′-quinocyanines with long N-alkyl substituents
Orlova,Kolchina,Zhuravlev,Shakirov,Gerasimova,Shelkovnikov
, p. 1233 - 1241 (2002)
2,2′-Quinocyanines with long alkyl substituents on one or both nitrogen atoms have been synthesized. 1H NMR spectroscopy has been used to study the processes occurring during the alkylation of the starting quinoline bases.
Deoxygenation of Epoxides with Carbon Monoxide
Maulbetsch, Theo,Jürgens, Eva,Kunz, Doris
, p. 10634 - 10640 (2020/07/30)
The use of carbon monoxide as a direct reducing agent for the deoxygenation of terminal and internal epoxides to the respective olefins is presented. This reaction is homogeneously catalyzed by a carbonyl pincer-iridium(I) complex in combination with a Lewis acid co-catalyst to achieve a pre-activation of the epoxide substrate, as well as the elimination of CO2 from a γ-2-iridabutyrolactone intermediate. Especially terminal alkyl epoxides react smoothly and without significant isomerization to the internal olefins under CO atmosphere in benzene or toluene at 80–120 °C. Detailed investigations reveal a substrate-dependent change in the mechanism for the epoxide C?O bond activation between an oxidative addition under retention of the configuration and an SN2 reaction that leads to an inversion of the configuration.
Palladium-Catalyzed Oxidative Dehydrosilylation for Contra-Thermodynamic Olefin Isomerization
Butcher, Trevor W.,Hanna, Steven,Hartwig, John F.,Wills, Tyler
, p. 8736 - 8741 (2020/09/23)
We report a newly developed, palladium-catalyzed dehydrosilylation of terminal alkylsilanes that combines with chain-walking hydrosilylation to create a one-pot isomerization of internal olefins to terminal olefins. This catalytic dehydrosilylation is one of the few examples of thermal catalytic functionalizations of unactivated alkylsilanes. The reaction involves transmetalation of an alkylsilane, β-hydride elimination, release of the terminal olefin, and reoxidation of the palladium catalyst. A variety of linear internal olefins underwent the overall isomerization to terminal olefins in good yields and in good regioselectivities. Particularly noteworthy, isomerizations occurring over seven carbon units proceeded in yields that are comparable to those of isomerizations occurring over one carbon unit.
