CuBr-Catalyzed Coupling of <i>N-</i>Tosylhydrazones and Terminal Alkynes: Synthesis of Benzofurans and Indoles
作者:Lei Zhou、Yi Shi、Qing Xiao、Yizhou Liu、Fei Ye、Yan Zhang、Jianbo Wang
DOI:10.1021/ol103009n
日期:2011.3.4
A new method for the synthesis of benzofurans or indoles via ligand-free CuBr-catalyzed coupling/cyclization of terminalalkynes with N-tosylhydrazones derived from o-hydroxy- or o-aminobenzaldehydes has been developed. A wide range of functional groups were found that are able to tolerate the reaction conditions.
Facile access to 2,2-diaryl 2<i>H</i>-chromenes through a palladium-catalyzed cascade reaction of <i>ortho</i>-vinyl bromobenzenes with <i>N</i>-tosylhydrazones
作者:Heng Zhang、Yinghua Yu、Xueliang Huang
DOI:10.1039/d0ob00978d
日期:——
A palladium-catalyzed cascade reaction of ortho-vinyl bromobenzenes with N-tosylhydrazones has been developed, which provides a facile approach to 2,2-disubstituted 2H-chromenes. The migration of palladium from the aryl to vinyl position is crucial, as the in situ produced vinyl palladium intermediate could further react with diazocompounds to generate the reactive species for the sequential annulation
Direct Synthesis of 2-Methylbenzofurans from Calcium Carbide and Salicylaldehyde <i>p</i>-Tosylhydrazones
作者:Rugang Fu、Zheng Li
DOI:10.1021/acs.orglett.8b00676
日期:2018.4.20
A new methodology for the construction of methyl-substituted benzofuran rings from the reactions of calcium carbide with salicylaldehyde p-tosylhydrazones/2-hydroxyacetophenone p-tosylhydrazones is described. Various 2-methylbenzofurans and 2,3-dimethylbenzofurans could be obtained in satisfactory yield by using a cuprous chloride catalyst. The advantages of this protocol include the use of a readily
Palladium-Catalyzed Tandem Reaction of Alkyne-Based Aryl Iodides and Salicyl<i>N</i>-Tosylhydrazones to Construct the Spiro[benzofuran-3,2′-chromene] Skeleton
作者:Xue Song Shang、Nian Tai Li、Deng Yuan Li、Pei Nian Liu
DOI:10.1002/adsc.201501150
日期:2016.5.19
aryl iodides and salicyl N‐tosylhydrazones has been achieved to afford a series of compounds containing the novel spiro[benzofuran‐3,2′‐chromene] scaffold in moderate to good yields. This efficient catalytic reaction, which tolerates various functional groups, combines alkyne‐based 5‐exo‐dig cyclization, palladium(II) carbene migratory insertion and intramolecular cyclization, generating three new bonds
A method was developed for the preparation of 3-(2,2-dichloroacetyl)-2H-chromen-2-ones and (E)-N′-(2-hydroxybenzylidene)-N,4-dimethylbenzenesulfono hydrazides by reacting salicyl N-tosylhydrazones with ethyl 4,4,4-trichloro-3-oxobutanoate and dimethyl (1-diazo-2-oxopropyl)-phosphonate (Bestmann-Ohira reagent) in presence of RuCl3 ⋅ 3H2O.