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
CuI-Catalyzed Selective 3-Alkylation of Indoles with <i>N</i>
-Tosylhydrazones and the I<sub>2</sub>
-Mediated Further Cyclization to Chromeno[2,3-<i>b</i>
]Indoles
作者:Chun-Bao Miao、Yan-Fang Sun、He Wu、Xiao-Qiang Sun、Hai-Tao Yang
DOI:10.1002/adsc.201800206
日期:2018.7.4
The CuI‐catalyzed reaction of indoles with N‐tosylhydrazones derived from the ortho‐/para‐hydroxybenzaldhydes affords selectively the C‐3 alkylated products rather than the N‐alkylated products. In addition, the I2‐mediated cyclization of the generated C‐3 alkylated products allows the concise synthesis of chromeno[2,3‐b]indole derivatives.
吲哚与碘化亚铜催化反应Ñ -tosylhydrazones从派生邻- /对-hydroxybenzaldhydes得到选择性地将Ç -3烷基化产物,而不是Ñ烷基化产品。此外,生成的C-3烷基化产物的I 2介导的环化反应可简化chromeno [2,3- b ]吲哚衍生物的合成。
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.