2<i>H</i>-Chromenes Generated by an Iron(III) Complex-Catalyzed Allylic Cyclization
作者:L. Calmus、A. Corbu、J. Cossy
DOI:10.1002/adsc.201500058
日期:2015.5.4
A straightforward method based on an iron(III) complex‐catalyzed cyclization of 2‐(1‐hydroxyallyl)phenols is reported to access a large variety of 2H‐chromenes. This method was applied to the total synthesis of a natural product, tephrowatsin B.
Claisen rearrangement of aryl propargyl ethers in poly(ethylene glycol)- a remarkable substituent and solvent effect
作者:Usha Roa、K.K. Balasubramanian
DOI:10.1016/s0040-4039(01)99839-9
日期:1983.1
The Claisen rearrangement of aryl propargyl ethers in poly(ethylene glycol) - 200 at 200°C affords products in good yields. Aryl propargyl ethers containing electron donating groups yield (2H)-benzopyrans and those containing electron withdrawing groups yield 2-methylbenzofurans.
The Au(I)-Catalyzed Intramolecular Hydroarylation of Terminal Alkynes Under Mild Conditions: Application to the Synthesis of 2<i>H</i>-Chromenes, Coumarins, Benzofurans, and Dihydroquinolines
作者:Rajeev S. Menon、Alison D. Findlay、Alex C. Bissember、Martin G. Banwell
DOI:10.1021/jo902032p
日期:2009.11.20
Operationally simple Au(I)-catalyzed intramolecularhydroarylation (IMHA) reactions of terminal alkynes that proceed in high yield and under very mild conditions are described. These processes involve low catalyst loadings, mild reaction temperatures, and short reaction times, require no cocatalysts or additives, and allow for the generation of a number of important heterocyclic motifs from readily
Synthesis of 2<i>H</i>-Chromenes through the Reduction of Chromones with 9-BBN
作者:Tetsuya Eguchi、Yukio Hoshino
DOI:10.1246/bcsj.74.967
日期:2001.5
reduced to 2H-1-benzopyrans through the 1,2-addition of 9-borabicyclo[3.3.1]nonane. Although transition-metal complexes did not have a catalytic effect on the reaction, only by using palladium(II) chloride, could both 2H-1-benzopyran and dihydro-1-benzopyran be obtained to a similar extent. Also, the reduction of chromone using other organoboranes led not to 2H-1-benzopyran, but rather to chromanone through