Fluoride-free Hiyama coupling by palladium abnormal N-heterocyclic carbene complexes

Sudipta Modak (1) , Manoj Kumar Gangwar (1) , Mitta Nageswar Rao (1) , Mahesh Madasu (1) , Alok Ch Kalita (1) , Vincent Dorcet (2) , Mayuri Arun Shejale , Ray J. Butcher (3) , Prasenjit Ghosh (1)

1 IIT Bombay - Indian Institute of Technology Bombay
2 ISCR - Institut des Sciences Chimiques de Rennes
3 Howard University

A series of palladium complexes of the abnormal N-heterocyclic carbene ligands of the type (a-NHC)PdI2(L) [L = NC5H5(1–3)b and PPh3(1–3)c] effectively catalyzed the Hiyama coupling of aryl bromides and iodides with PhSi(OMe)3 under the highly desired fluoride-free conditions. Interestingly enough, the pyridine based trans-(1–3)b complexes and a PPh3 derived cis-3c complex exhibited higher yields than the related PPh3 derived trans-(1–2)c complexes. The superior performances of the pyridine based trans-(1–3)b complexes and the PPh3 derived cis-3c complex have been correlated to a tighter binding of the a-NHC ligand to the palladium center in these complexes, leading to a greater (a-NHC) ligand influence on the metal center partaking in the catalysis

Domains: Chemical Sciences

Sudipta Modak, Manoj Kumar Gangwar, Mitta Nageswar Rao, Mahesh Madasu, Alok Ch Kalita, et al.. Fluoride-free Hiyama coupling by palladium abnormal N-heterocyclic carbene complexes. Dalton Transactions, 2015, 44 (40), pp.17617--17628. ⟨10.1039/C5DT02317C⟩. ⟨hal-01224518⟩