- Synthesis of pyrano[2,3-: F] chromen-2-ones vs. pyrano[3,2-g] chromen-2-ones through site controlled gold-catalyzed annulations
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Regioselective access to 10-substituted-2H,8H-pyrano[2,3-f]chromen-2-ones through the gold-catalyzed intramolecular hydroarylation of readily available 7-(prop-2-yn-1-yloxy)-2H-chromen-2-one derivatives at their C-8 congested position was investigated by tuning the electronic and steric properties of the ligand on the gold complex. On the other hand, the combination of the JohnPhosAu(MeCN)SbF6 catalyzed intramolecular hydroarylation of 8-iodo-7-(prop-2-yn-1-yloxy)-2H-chromen-2-one derivatives followed by selective palladium/formate C-I reduction allows for the exclusive formation of 2H,8H-pyrano[3,2-g]chromen-2-one regioisomers. The development of these two protocols provides versatile synthetic tools required for exploring the biological activities of these new pyranocoumarin derivatives.
- Arcadi, Antonio,Ciogli, Alessia,Fabrizi, Giancarlo,Fochetti, Andrea,Franzini, Roberta,Ghirga, Francesca,Goggiamani, Antonella,Iazzetti, Antonia
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supporting information
p. 10065 - 10072
(2019/12/23)
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- Cesium fluoride-mediated claisen rearrangements of phenyl propargyl ethers: Substituent effects of an orthoalkoxy group on the benzene ring or modified propargyl residues
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The expected 7-alkoxy-2-methylbenzo[b]furans were effectively given in the CsF-mediated Claisen rearrangement of phenyl propargyl ethers with an o-alkoxy substituent on the benzene ring. On the other hand CsF did not affect the production of the corresponding benzo[b]furans when ethers, carrying a propargyl residue modified by either 1,1-dimethyl or 3-ethoxycarbonyl functions, were used as substrates in the rearrangement.
- Ishikawa, Tsutomu,Mizutani, Akiko,Miwa, Chizue,Oku, Yumie,Komano, Naoko,Takami, Atsuya,Watanabe, Toshiko
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p. 2261 - 2272
(2007/10/03)
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