Visible Light-Induced Selective Generation of Radicals from Organoborates by Photoredox Catalysis
作者:Yusuke Yasu、Takashi Koike、Munetaka Akita
DOI:10.1002/adsc.201200588
日期:2012.12.14
A new strategy for the generation of carbon-centered radicals via oxidation of alkyl-, allyl-, benzyl- and arylborates by visible-light-driven single electron transfer (SET) photoredoxcatalysis has been established. The generated radicals smoothly react with TEMPO and electron-deficient alkenes to afford CO and CC coupling products, respectively. In this radical initiating system, cyclic organo(triol)borates
Metal-Free Heterogeneous Semiconductor for Visible-Light Photocatalytic Decarboxylation of Carboxylic Acids
作者:Jiale Shi、Tao Yuan、Meifang Zheng、Xinchen Wang
DOI:10.1021/acscatal.0c05211
日期:2021.3.5
ceramic boron carbon nitrides (BCN). With visiblelight irradiation, BCN oxidize carboxylic acids to give carbon-centered radicals, which were trapped by hydrogen atom donors or employed in the construction of the carbon–carbonbond. In this system, both (hetero)aromatic and aliphatic acids proceed the decarboxylation smoothly, and C–H, C–D, and C–C bonds are formed in moderate to high yields (35 examples
Photochemical benzylic radical arylation promoted by supported Pd nanostructures
作者:Teresa A. Gawargy、Paolo Costa、Anabel E. Lanterna、Juan C. Scaiano
DOI:10.1039/d0ob01227k
日期:——
We report a novel way to promote photochemical benzylic radical arylations using Pd nanostructures. Traditional benzylic radical reaction pathways are challenged by the presence of metal centres that provoke unprecedented regioselectivity towards more synthetically relevant C(sp3)–C(sp2) couplings. This new C–H activation pathway is rationalised by means of a pseudo-persistent radical effect facilitated
Diels–Alder reaction of tetraarylcyclopentadienones with benzo[<i>b</i>]thiophene <i>S</i>,<i>S</i>-dioxides: an unprecedented de-oxygenation <i>vs.</i> sulfur dioxide extrusion
作者:Palani Manikandan、Jayachandran Karunakaran、Elumalai Varathan、Georg Schreckenbach、Arasambattu K Mohanakrishnan
DOI:10.1039/d0cc05842d
日期:——
benzo[b]thiophene dioxides in xylenes at reflux led to the formation of tetra aryl-substituted dibenzothiophene as well as penta aryl-substituted benzene analogues depending on the influence of aryl substituents present on cyclopentadienones. The intermediate dihydrodibenzothiophene-dioxides underwent aromatization either through de-oxygenation or extrusion of sulfur dioxide to furnish substituted dibenzothiophenes
四芳基环戊二烯酮与二甲苯中的苯并[ b ]噻吩二氧化物在回流下的Diels-Alder反应导致四芳基取代的二苯并噻吩以及五芳基取代的苯类似物的形成,具体取决于芳基取代基对环戊二烯的影响。中间体二氢二苯并噻吩二氧化物通过脱氧或挤出二氧化硫进行芳构化,以提供取代的二苯并噻吩或苯。
A Direct S
<sub>0</sub>
→T
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<i>n</i>
</sub>
Transition in the Photoreaction of Heavy‐Atom‐Containing Molecules
the Grotthuss-Draper law, light must be absorbed by a substrate to initiate a photoreaction. There have been several reports, however, on the promotion of photoreactions using hypervalent iodine during irradiation with light from a non-absorbing region. This contradiction gave rise to a "mystery" regarding photoreactions involving hypervalent iodine. We demonstrated that the photoactivation of hypervalent