Synthesis of 2,5-Diaryl-1,5-dienes from Allylic Bromides Using Visible-Light Photoredox Catalysis
摘要:
Visible-light photoreductive coupling of 2-arylallyl bromides in the presence of the photocatalyst Ru(bpy)(3)(PF6)(2), a Hantzsch ester, and i-Pr2NEt gives 2,5-diaryl-1,5-dienes in high yield. This method avoids the use of stoichiometric metal reductants and is compatible with the presence of halogen, alkyl, electron-donating, and electron-withdrawing substituents on the aromatic ring.
Acetylene as a Dicarbene Equivalent for Gold(I) Catalysis: Total Synthesis of Waitziacuminone in One Step
作者:Dagmar Scharnagel、Imma Escofet、Helena Armengol‐Relats、M. Elena Orbe、J. Nepomuk Korber、Antonio M. Echavarren
DOI:10.1002/anie.201915895
日期:2020.3.16
The gold(I)-catalyzed reaction of acetylene gas with alkenes leads to (Z,Z)-1,4-disubstituted 1,3-butadienes and biscyclopropanes depending on the donor ligand on gold(I). Acetylene was generated in situ from calcium carbide and water in a user-friendly procedure. Reaction of acetylene with 1,5-dienes gives rise stereoselectively to tricyclo[5.1.0.02,4 ]octanes. This novel double cyclopropanation has
Studies of the Electron-Promoted Cope Cyclization of 2,5-Phenyl-Substituted 1,5-Hexadiene Radical Anions
作者:Silvi A. Chacko、Paul G. Wenthold
DOI:10.1021/jo0618775
日期:2007.1.1
groups. Ions were formed by the thermalattachment of electrons in the gas phase. Structures of the molecular radical anions were probed to determine whether they undergo cyclization to a cyclohexane-1,4-diyl anion structure by examining chemical reactivity with neutral reagents including carbon dioxide, carbon disulfide, and nitric oxide. First-order rate constants for the reactions of ions were measured
Evidence for Significant Through-Space and Through-Bond Electronic Coupling in the 1,4-Diphenylcyclohexane-1,4-diyl Radical Cation Gained by Absorption Spectroscopy and DFT Calculations
作者:Hiroshi Ikeda、Yosuke Hoshi、Hayato Namai、Futoshi Tanaka、Joshua L. Goodman、Kazuhiko Mizuno
DOI:10.1002/chem.200700820
日期:2007.11.16
formation of an intense electronicabsorptionband at 476 nm, which is attributed to the 1,4-diphenylcyclohexane-1,4-diyl radicalcation. The absorption maximum (lambda(ob)) of this transient occurs at a longer wavelength than is expected for either the cumyl radical or the cumyl cation components. Substitution at the para positions of the phenyl groups in this radicalcation by CH(3)O, CH(3), F, Cl
Synthesis of 2,5-Diaryl-1,5-dienes from Allylic Bromides Using Visible-Light Photoredox Catalysis
作者:Gerald Pratsch、Larry E. Overman
DOI:10.1021/acs.joc.5b01962
日期:2015.11.20
Visible-light photoreductive coupling of 2-arylallyl bromides in the presence of the photocatalyst Ru(bpy)(3)(PF6)(2), a Hantzsch ester, and i-Pr2NEt gives 2,5-diaryl-1,5-dienes in high yield. This method avoids the use of stoichiometric metal reductants and is compatible with the presence of halogen, alkyl, electron-donating, and electron-withdrawing substituents on the aromatic ring.