Copper-Catalysed Allylic Substitution Using 2,8,14,20-Tetrapentylresorcinarenyl-Substituted Imidazolium Salts

WOS: 000364968800013
Unsymmetrical imidazolium salts, each having one nitrogen atom (N1) substituted by a cavity-shaped TPR group (TPR = 2,8,14,20-tetrapentylresorcinaren-5-yl), were tested in situ as proligands for the copper-catalysed allylic arylation of cinnamyl bromide with arylmagnesium halides. The catalytic systems produced mixtures of linear (l) and branched (b) arylated compounds in variable proportions, with the b/l ratio being the highest (78:22) for the most crowded imidazolium salt used, namely that in which the second nitrogen atom (N2) was substituted by a mesityl group. An N-heterocyclic carbene complex obtained from one of the imidazolium salts was characterised by an X-ray diffraction study.
Scientific and Technological Research of Turkey (TUBITAK-BIDEB); International Research Fellowship Programme; French Agence Nationale de la Recherche (ANR) [ANR-12-BS07-0001-01-RESICAT]
The authors thank the Scientific and Technological Research of Turkey (TUBITAK-BIDEB), the International Research Fellowship Programme for grants to M. K. and N. S., and the French Agence Nationale de la Recherche (ANR) (ANR-12-BS07-0001-01-RESICAT) for financial support.