Mild copper-catalyzed vinylation reactions of azoles and phenols with vinyl bromides.
An efficient and straightforward copper-catalyzed method allowing vinylation of N- or O-nucleophiles with di- or trisubstituted vinyl bromides is reported. The procedure is applicable to a broad range of substrates since N-vinylation of mono-, di-, and triazoles as well as O-vinylation of phenol derivatives can be performed with catalytic amounts of copper iodide and inexpensive nitrogen ligands 3 or 8. In the case of more hindered vinyl bromides, the use of the original bidentate chelator 8 was shown to be more efficient to promote the coupling reactions than our key tetradentate ligand 3. The corresponding N-(1-alkenyl)azoles and alkenyl aryl ethers are obtained in high yields and selectivities under very mild temperature conditions (35-110 degrees C for N-vinylation reactions and 50-80 degrees C for O-vinylation reactions). Moreover, to our knowledge, this method is the first example of a copper-catalyzed vinylation of various azoles. Finally, this protocol, practical on a laboratory scale and easily adaptable to an industrial scale, is very competitive compared to the existing methods that allow the synthesis of such compounds.
Taillefer
Marc
M
CNRS UMR 5076, Hétérochimie moléculaire et macromoléculaire Ecole Nationale Supérieure de Chimie de Montpellier, 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 5, France. Marc.taillefer@enscm.fr
Ouali
Armelle
A
Renard
Brice
B
Spindler
Jean-Francis
JF