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Cross‐coupling reactions in water using ionic liquid‐based palladium(II)–phosphinite complexes as outstanding catalysts
Author(s) -
Meriç Nermin,
Aydemir Murat,
Işik Uğur,
Ocak Yusuf Selim,
Rafikova Khadichakhan,
Paşa Salih,
Kayan Cezmi,
Durap Feyyaz,
Zazybin Alexey,
Temel Hamdi
Publication year - 2014
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.3205
Subject(s) - chemistry , phosphinite , phenylboronic acid , catalysis , aryl , palladium , ionic liquid , medicinal chemistry , homogeneous catalysis , suzuki reaction , coupling reaction , nuclear chemistry , inorganic chemistry , organic chemistry , alkyl
Two new phosphinite ligands based on ionic liquids [(Ph 2 PO)C 7 H 14 N 2 Cl]Cl ( 1 ) and [(Cy 2 PO)C 7 H 14 N 2 Cl]Cl ( 2 ) were synthesized by reaction of 1‐(3‐chloro‐2‐hydoxypropyl)‐3‐methylimidazolium chloride, [C 7 H 15 N 2 OCl]Cl, with one equivalent of chlorodiphenylphosphine or chlorodicyclohexylphosphine, respectively, in anhydrous CH 2 Cl 2 and under argon atmosphere. The reactions of 1 and 2 with MCl 2 (cod) (M = Pd, Pt; cod = 1,5‐cyclooctadiene) yield complexes cis ‐[M([(Ph 2 PO)C 7 H 14 N 2 Cl]Cl) 2 Cl 2 ] and cis ‐[M(Cy 2 PO)C 7 H 14 N 2 Cl]Cl) 2 Cl 2 ], respectively. All complexes were isolated as analytically pure substances and characterized using multi‐nuclear NMR and infrared spectroscopies and elemental analysis. The catalytic activity of palladium complexes based on ionic liquid phosphinite ligands 1 and 2 was investigated in Suzuki cross‐coupling . They show outstanding catalytic activity in coupling of a series of aryl bromides or aryl iodides with phenylboronic acid under the optimized reaction conditions in water. The complexes provide turnover frequencies of 57 600 and 232 800 h −1 in Suzuki coupling reactions of phenylboronic acid with p ‐bromoacetophenone or p ‐iodoacetophenone, respectively, which are the highest values ever reported among similar complexes for Suzuki coupling reactions in water as sole solvent in homogeneous catalysis . Furthermore, the palladium complexes were also found to be highly active catalysts in the Heck reaction affording trans ‐stilbenes. Copyright © 2014 John Wiley & Sons, Ltd.