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Double C–H Functionalization to Construct Polycyclic Heteroarenes Catalyzed by an Ionic Salt of a Pd Complex with an N‐Heterocyclic Carbene Ligand
Author(s) -
Ghosh Sanjay Kumar,
Kuo BingChiuan,
Chen HsiangYu,
Li JiaYing,
Liu ShuangDe,
Lee Hon Man
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201500417
Subject(s) - chemistry , carbene , metathesis , ligand (biochemistry) , salt (chemistry) , bromide , pyridine , medicinal chemistry , acetonitrile , ionic bonding , ionic compound , surface modification , salt metathesis reaction , catalysis , organic chemistry , polymerization , ion , polymer , biochemistry , receptor
A new ionic salt, cis ‐[Pd(L)(PPh 3 )(H 2 O) 2 ](SO 3 CF 3 ) 2 ( A ), in which L is an amido‐functionalized N‐heterocyclic carbene (NHC) ligand, has been prepared by the salt metathesis reaction between [Pd(L)(PPh 3 )Cl 2 ] and AgOTf in wet acetonitrile. It was successfully characterized by NMR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction analysis. Complex A was found to be effective in catalyzing the double C–H functionalization of various nitrogen‐ and sulfur‐containing heteroarenes to form fused polycyclic heteroaromatic compounds with alkynes in the presence of Cu(OAc) 2 and tetra‐ n ‐butylammonium bromide. Indoles, thiophenes, imidazo[1,2‐ a ]pyridine, and imidazoles were used as substrates. In particular, intriguing imidazo[5,1,2‐ cd ]indolizine compounds could be obtained under the conditions employed.