1-Triflylpyrroles as efficient dienophiles in normal electron demand [4+2] cycloaddition reactions under pressure
作者:Antony Chrétien、Isabelle Chataigner、Serge R. Piettre
DOI:10.1039/b414978e
日期:——
1-Triflylpyrroles bearing acetyl group(s) on position 3, or 2 and 4, are efficient dienophiles in normal electron demand Diels-Alder reactions activated by high pressures and Lewis acids.
Tuning the reactivity and chemoselectivity of electron-poor pyrroles as dienophiles in cycloadditions with electron-rich dienes
作者:Antony Chrétien、Isabelle Chataigner、Serge R. Piettre
DOI:10.1016/j.tet.2005.06.016
日期:2005.8
Activation by Lewis acid catalysis and high pressure allows pyrrole derivatives to react with electron-rich dienes in normal electron demand [4+2] cycloadditions, provided that the aromatic ring is substituted by at least two electron-withdrawing groups. The dienophilic behavior of the heterocycle is expressed through the involvement of either the aromatic carbon–carbon double bond in an all-carbon