The dawn of old stars: Classic xanthene dyes like eosin Y (gr. εoς=goddess of dawn) and green‐light irradiation can replace precious metal complexes for the organocatalytic asymmetric α‐alkylation of aldehydes, thus rendering the process purely organic.
A Free‐Radical Reduction and Cyclization of Alkyl Halides Mediated by FeCl
<sub>2</sub>
作者:Feba Thomas Pulikottil、Ramadevi Pilli、Vetrivelan Murugesan、Chandu G. Krishnan、Ramesh Rasappan
DOI:10.1002/cctc.201900230
日期:2019.5.20
Iron mediated catalytic reactions are of great interest in the field of organic synthesis because they are economic and naturally abundant. However, the use of iron catalyst in the field of free radicalcyclization or reduction of alkyl halides remains limited. Here we describe the use of an unprecedented combination of iron and zinc in the reduction and 5‐exo‐trig radicalcyclization of alkyl halides
Electron-Transfer Photoredox Catalysis: Development of a Tin-Free Reductive Dehalogenation Reaction
作者:Jagan M. R. Narayanam、Joseph W. Tucker、Corey R. J. Stephenson
DOI:10.1021/ja9033582
日期:2009.7.1
We report an operationally simple, tin-free reductive dehalogenation system utilizing the well-known visible-light-activated photoredox catalyst Ru(bpy)(3)Cl(2) in combination with (i)Pr(2)NEt and HCO(2)H or Hantzsch ester as the hydrogen atom donor. Activated C-X bonds may be reduced in good yields with excellent functional-group tolerance and chemoselectivity over aryl and vinyl C-X bonds. The proposed
Dehalogenation of functionalized alkyl halides in water at room temperature
作者:Nicholas A. Isley、Matt S. Hageman、Bruce H. Lipshutz
DOI:10.1039/c4gc01733a
日期:——
Alkyl bromides and chlorides can be reduced to the corresponding hydrocarbons utilizing zinc in the presence of an amine additive. The process takes place in water at ambient temperatures, enabled by a commercially available designer surfactant. The reaction medium can be readily recycled, and the amount of organic solvent invested for product isolation is minimal, leading to very low E Factors.
Application of Microflow Conditions to Visible Light Photoredox Catalysis
作者:Matthias Neumann、Kirsten Zeitler
DOI:10.1021/ol3005529
日期:2012.6.1
Applications of microflow conditions for visiblelight photoredox catalysis have successfully been developed. Operationally simple microreactor and FEP (fluorinated ethylene propylene copolymer) tube reactor systems enable significant improvement of several photoredox reactions using different photocatalysts such as [Ru(bpy)3]2+ and Eosin Y. Apart from rate acceleration, this approach facilitates previously