Journal ArticleDOI
The role of proton donors in SmI2-mediated ketone reduction: new mechanistic insights.
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TLDR
Water has a high affinity for SmI2 (compared to that of the alcohols), and the onset of coordination at relatively low concentrations channels the reaction through a mechanistically distinct pathway.Abstract:
The effects of proton donors (alcohols and water) on the rate of reduction of acetophenone by SmI2 have been examined utilizing stopped-flow spectrophotometric studies. The rate orders with respect to proton source and the kinetic isotope effects were determined as well. The reaction was first-order in phenol, 2,2,2-trifluoroethanol, methanol, and ethanol and zero-order in 2-propanol and 2-methyl-2-propanol when 25 equiv of proton source were used in the reduction. Methanol, ethanol, 2,2,2-trifluoroethanol, and phenol also showed a direct correlation between the pKa of the alcohol and the rate of reduction. Under the same conditions, water had a fractional rate order of 1.4. Further studies showed that water has a rate order of 1 at lower concentrations ( 80 equiv). These results clearly indicate that the nature of the proton donor and its concentration affects the rates of reduction. Water has a high affinity for SmI2 (compared to that of the alco...read more
Citations
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Journal ArticleDOI
Samarium(II)-iodide-mediated cyclizations in natural product synthesis.
TL;DR: A review, cyclization reactions in natural product synthesis of 4-9 membered and larger rings were discussed.
Journal ArticleDOI
Cross-coupling reactions using samarium(II) iodide.
Journal ArticleDOI
Samarium(II) Iodide Mediated Reductions − Influence of Various Additives
Anders Dahlén,Göran Hilmersson +1 more
TL;DR: An overview of the current knowledge of the reagent SmI2 as a reducing agent, in particular with additives that increase its reactivity is given in this article, where the use of various proton sources is covered, as well as the effect of co-solvents.
Journal ArticleDOI
Recent advances in the chemoselective reduction of functional groups mediated by samarium(II) iodide: a single electron transfer approach.
TL;DR: Samarium(II) iodide reductants have emerged as powerful single electron donors for the highly chemoselective reduction of common functional groups, which opens up new prospects for unprecedented transformations via radical intermediates under mild regio-, chemo- and diastereoselectives conditions that are fully orthogonal to hydrogenation or metal-hydride mediated processes.
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Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future
Markus D. Kärkäs,Bryan S. Matsuura,Timothy M. Monos,Gabriel Magallanes,Corey R. J. Stephenson +4 more
TL;DR: This review examines the development of transition-metal catalyzed reactions and the insights shared between the homogeneous and heterogeneous catalytic systems towards the ultimate goal of valorizing lignin to produce value-added products.
References
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Journal ArticleDOI
Sequencing Reactions with Samarium(II) Iodide.
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Additive and solvent effects on samarium diiodide reductions: the effects of water and DMPU
Eietsu Hasegawa,Dennis P. Curran +1 more
TL;DR: In this paper, the role of water and DPMU on samarium(II) iodide reduction is considered and examples of reduction reactions are presented, where water is used to remove water from samarium iodide.
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Evidence for ionic samarium(II) species in THF/HMPA solution and investigation of their electron-donating properties
TL;DR: Comparison of rate constants for electron transfer (ET) reactions involving aromatic radical anions revealed that none of the reactions studied can be classified as outer-spheres ET processes and that the inner-sphere electron-donating abilities of the [Sm(hmpa)4(thf)2]2+ 2I- and SmI2 complexes are comparable.
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Rapid SmI2-mediated reductions of alkyl halides and electrochemical properties of SmI2/H2O/amine.
TL;DR: The results of these experiments show that the combination of SmI(2)/H(2)O/amine provides a fundamentally novel and useful approach to enhance the reactivity of Smi(2).