Direct C-H Bond Arylation of C2-Blocked Pyrrole with Aryl Halides Using Palladium(II)-N-Heterocyclic Carbene Catalysts
CHEMISTRYSELECT, vol.3, no.20, pp.5600-5607, 2018 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 3 Issue: 20
- Publication Date: 2018
- Doi Number: 10.1002/slct.201801045
- Journal Name: CHEMISTRYSELECT
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.5600-5607
- Keywords: Benzimidazolium salt, Direct C-H bond arylation, N-Heterocyclic carbene, Palladium, Pyrrole, ROOM-TEMPERATURE, DERIVATIVES, HETEROAROMATICS, FUNCTIONALIZATION, COMPLEXES, THIAZOLES, ACCESS, SYSTEM, FURANS, C-2
- Inonu University Affiliated: Yes
Abstract
Herein we report synthesis of seven new palladium(II)-NHC complexes with the general formula [PdX2(NHC)(2)], (NHC=1,3-dialkylbenzimidazol-2-ylidene, X = Cl or Br). The structures of all the new compounds were characterized by (HNMR)-H-1, (CNMR)-C-13, FT-IR spectroscopy and elemental analysis techniques. The catalytic activities of palladium(II)-NHC complexes were tested in the direct C-H bond arylation of C2-blocked pyrrole with various aryl halides in presence of 1mol% catalyst loading at 120 degrees C for 1-16 h. Under the given conditions, palladium(II)-NHC complexes showed the good catalytic performance for the direct C-H bond arylation of C2-blocked pyrrole with aryl bromides, and with readily available and inexpensive aryl chlorides. In all cases, the C-H bond arylation regioselectively produced C5-arylated products in moderate to high yields.