Microwave-Promoted Palladium-Catalysed Oxyarylation of Dihydronaphthalene and Chromenes by o-Iodophenols and Its Acetates
作者:Raquel A. C. Leão、Vagner D. Pinho、Artur S. Coelho、Camilla D. Buarque、Paula F. Moraes、Diego A. Alonso、Carmen Nájera、Paulo R. R. Costa
DOI:10.1002/ejoc.201100365
日期:2011.6
The oxyarylation of dihydronaphthalene (1a), two electron-rich (1b,c) and one electron-poor (2) chromenes with different o-iodophenols and their acetates 3a–h has been investigated by using either Pd(OAc)2 (10 mol-%) as precatalyst and Ag2CO3 as base in acetone as solvent or oxime palladacycle 5 as precatalyst and dicyclohexylamine as base in DMA/H2O. The reactions, which were strongly accelerated
A highly adaptable catalyst/substrate system for the synthesis of substituted chromenes
作者:Aaron Aponick、Berenger Biannic、Michael R. Jong
DOI:10.1039/c0cc01961e
日期:——
The gold(I)-catalyzed endo-cyclization of o-(1-hydroxyallyl)phenols to form chromenes is reported. The title compounds are prepared in high yield from readily available substrates. The system tolerates both electron rich and deficient aryl rings and a high degree of substitution on the allyl moiety.
Radical cyclisation : synthesis of 4H-furo(3,2-c)-1-benzopyrans
作者:G Ariamala、K.K Balasubramanian
DOI:10.1016/0040-4039(88)85155-4
日期:1988.1
3,4-dihydro-3-bromo-4-(prop-2-ynyloxy)-2H-1-benzopyrans (3) undergo radicalcyclisation when treated with nBu3SnH and AIBN to give good yield of 2,3,3a,9b-tetrahydro-3-methylene-4H-furo (3,2-c)benzopyrans (4).
Asymmetricaddition of arylboronicacids to 2H-chromenes proceeded in the presence of a hydroxorhodium/chiral diene catalyst to give 3-arylchromanes in high yields with high enantioselectivity. The reaction involves 1,4-Rh shift before protonation to release the addition product and to regenerate the hydroxorhodium species.
Asymmetric Synthesis of Chiral Chromanes by Copper‐Catalyzed Hydroamination of 2
<i>H</i>
‐Chromenes
作者:Qingjing Yang、Sifeng Li、Jun (Joelle) Wang
DOI:10.1002/cctc.202000601
日期:2020.6.18
A copper/(R )‐DTBM‐SEGPHOS‐catalyzed enantioselective hydroamination of 2H ‐chromenes employing hydrosilanes and hydroxylamine esters has been developed. This protocol offers a highly efficient and direct route for accessing a series of 4‐aminochromanes in 50–88 % yields with 59–99 % enantioselectivities under mild reaction conditions.