- Regioselective Hydroalkylation of Vinylarenes by Cooperative Cu and Ni Catalysis
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Disclosed here is a dual copper and nickel catalytic system with a silyl hydride source for promoting the linear selective hydroalkylation of vinylarenes. This carbon–carbon bond-forming protocol is applied to couple a variety of functionalized vinylarenes with alkyl halides applying a nickel(II) NNN pincer complex in the presence of an NHC-ligated copper catalyst. This combination allows for a 1 mol % loading of the nickel catalyst leading to turnover numbers of up to 72. Over 40 examples are presented, including applications for pharmaceutical diversification. Labeling experiments demonstrated the regioselectivity of the reaction and revealed that the copper catalyst plays a crucial role in enhancing the rate for formation of the reactive linear alkyl nickel complex. Overall, the presented work provides a complimentary approach for hydroalkylation reactions, whilst providing a preliminary mechanistic understanding of the cooperativity between the copper and nickel complexes.
- Ravn, Anne K.,Johansen, Martin B.,Skrydstrup, Troels
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supporting information
(2021/12/14)
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- Synthesis and insecticidal activity of novel carbamate derivatives as potential dual-binding site acetylcholinesterase inhibitors
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In biological systems, bivalent ligands often possess increased functional affinity for their receptors compared with monovalent ligands. On the basis of the structure of acetylcholinesterase (AChE), a series of novel carbamate heterodimetic derivatives w
- Ma, Hong-Ju,Xie, Ru-Liang,Zhao, Qian-Fei,Mei, Xiang-Dong,Ning, Jun
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experimental part
p. 12817 - 12821
(2011/10/09)
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- Cyclotriveratrylene models for proteins: 3:1 subsite differentiation and modulation of the redox potential
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The potential of cyclotriveratrylene (ctv) (2,3,7,8,12,13-hexamethoxy-10,15-dihydro-5H-tribenzocyclo-nonene) trithiols as ligands that can easily be functionalised and show subsite differentiation in their complexes with clusters has been explored.The cluster complexes of tris(2-sulfanylethoxy)- and tris(3-sulfanyl-methylbenzyloxy)-functionalised ctvs have been studied by core-extrusion experiments, spectroscopy and electrochemical techniques.With 2- as starting material a cluster complex was obtained in which the unique Fe and its co-ordinating Cl was turned into the cavity and show no reactivity.Starting with the more bulky t)4>2- the unique iron points outwards and is susceptible to substitution reactions.The effects of hydrogen bonding and electron density on the redox potential of the cluster complex have been investigated.The redox potential becomes more negative when the length of the spacer between the ctv and cluster core is increased, which is explained by the longer distance between the cluster and the electron-withdrawing phenoxy moiety of the ctv.The synthesis of ctv derivatives with one thiol and one alcohol functionality per phenyl unit, and comparison with corresponding derivatives where hydrogen bonding is not possible, showed that no significant differences were found.The effects of a substituent in an aromatic amide group that could hydrogen bond to the co-ordinated thiol were investigated.A weak effect, in the direction expected, was found upon substitution of methyl for H.
- Strijdonck, Gino P. F. van,Haare, John A. E. H. van,Hoenen, Paulus J.M.,Schoor, Roger C. G. M. van den,Feiters, Martinus C.,et al.
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p. 449 - 462
(2007/10/03)
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