14976-54-6Relevant articles and documents
Radical-triggered three-component coupling reaction of alkenylboronates, α-halocarbonyl compounds, and organolithium reagents: The inverse ylid mechanism
Tappin, Nicholas D. C.,Gn-Gi-lux, Manuel,Renaud, Philippe
, p. 11498 - 11502 (2018)
An operationally simple protocol to affect a radical addition to alkenylboronates that spontaneously undergo a [1,2]-metalate shift is described. Overall, the reaction is a three-component coupling of an organolithium, alkenylboronic ester, and halide which takes place with broad scope and good to excellent yields. Experimental mechanistic investigations support the formation of a boron inverse ylid intermediate.
Cyclopropanation of Terminal Alkenes through Sequential Atom-Transfer Radical Addition/1,3-Elimination
Tappin, Nicholas D. C.,Michalska, Weronika,Rohrbach, Simon,Renaud, Philippe
supporting information, p. 14240 - 14244 (2019/08/26)
An operationally simple method to affect an atom-transfer radical addition of commercially available ICH2Bpin to terminal alkenes has been developed. The intermediate iodide can be transformed in a one-pot process into the corresponding cyclopropane upon treatment with a fluoride source. This method is highly selective for the cyclopropanation of unactivated terminal alkenes over non-terminal alkenes and electron-deficient alkenes. Due to the mildness of the procedure, a wide range of functional groups such as esters, amides, alcohols, ketones, and vinylic cyclopropanes are well tolerated.
Aminopyridine-Borane Complexes as Hydrogen Atom Donor Reagents: Reaction Mechanism and Substrate Selectivity
Barth, Florian,Achrainer, Florian,Pütz, Alexander M.,Zipse, Hendrik
supporting information, p. 13455 - 13464 (2017/10/05)
Lewis base-borane complexes are shown to be potent hydrogen atom donors in radical chain reduction reactions. Results obtained in 1H, 11B, and 13C NMR measurements and kinetic experiments support a complex reaction mechanism involving the parent borane as well as its initial reaction products as active hydrogen atom donors. Efficient reduction reactions of iodides, bromides, and xanthates in apolar solvents rely on initiator systems generating oxygen-centered radicals under thermal conditions and pyridine-borane complexes carrying solubilizing substituents. In contrast to tin hydride reagents, the pyridine-boranes reduce xanthates faster than the corresponding iodides.
Effect of Lewis acids and low temperature initiators on the allyl transfer reaction involving phthalimido-N-oxyl radical
Patil, Shradha,Chen, Liang,Tanko, James M.
supporting information, p. 7029 - 7033 (2015/01/09)
Previously, we reported allyl transfer reactions of allyl bromide and allyl phthalimido-N-oxyl substrates with hydrocarbons that result in CC bond formation. In both cases, efficient chain transfer processes along with high reaction yields were observed. Since PINO chemistry leads to an environmentally friendly method of hydrocarbon functionalization, additional studies were performed in order to improve the process. To expand the utility of this reaction, we carried out experiments to optimize reaction conditions and tested the effect of Lewis acids and low temperature initiators. Although allyl-PINO substrates reacted slightly slower than the bromides, the reactions were cleaner with little or no side products. The chain lengths for these reactions were compromised at lower temperatures, attributable to the high activation energy required for the hydrogen atom abstraction by PINO. The addition of a Lewis acid catalyst (AlCl3) improves the product yield and reaction rate, possibly due to the formation of a PINO/AlCl3 complex which lowers the activation energy for hydrogen abstraction step.
Thermal and photochemical fragmentation of α,α-dialkoxybenzyl radicals: A comparison of the thermal reactions with laser induced fragmentations by using laser flash and laser-jet photolyses
Banks,Scaiano,Adam, Waldemar,Oestrich, Rolf Schulte
, p. 2473 - 2477 (2007/10/02)
The thermal and photochemical cleavage of α,α-dialkoxybenzyl radicals has been examined using a combination of techniques, including two-laser two-color laser flash photolysis and the laser-jet technique. For the parent α,α-dimethoxybenzyl radical photofragmentation occurs with a quantum yield of 0.80. The study of several unsymmetrically substituted radicals (e.g., methoxyisopropoxy) leads to the conclusion that the photoinduced fragmentation shows no selectivity. In contrast, the thermal decomposition of the radicals shows that fragmentation follows the expected radical stabilities, i.e., isopropyl > ethyl > methyl, the differences being almost exclusively due to changes in the activation energy. By comparing with literature data for methyl elimination it is possible to estimate the rate constants for fragmentation at 56°C as 213, 1380, and 16 600 s-1 for methyl, ethyl, and isopropyl elimination.
THE LEWIS ACID CATALYSED REACTION OF TRANS-HYPONITRITE ION WITH ALKYL HALIDES
Mendenhall, G. David
, p. 451 - 452 (2007/10/02)
Sodium and other inorganic trans-hyponitrites afford tert-alkyl hyponitrites in good yield from the corresponding alkyl bromide or chloride in the presence of weak Lewis acids.
