New ligands for a general palladium-catalyzed amination of aryl and heteroaryl chlorides.
The synthesis and application of monodentate N-substituted heteroarylphosphines is described. In general, the ligands are conveniently prepared by selective metallation at the 2-position of the respective N-substituted heterocycle (pyrrole, indole) by using n-butyllithium/tetramethylethylenediamine (TMEDA) followed by quenching with dialkyl- or diarylchlorophosphines. Of the different ligands prepared, the new dialkyl-2-(N-arylindolyl)phosphines (cataCXium P) perform excellently in the palladium-catalyzed amination of aryl and heteroaryl chlorides. Coupling of both activated and deactivated chloroarenes proceeds under mild conditions (room temperature to 60 degrees C). By using optimized conditions remarkable catalyst productivity (total turnover number, TON, up to 8000) and activity (turnover frequency, TOF=14000 h(-1) at 75% conversion) are observed.
Rataboul
Franck
F
Leibniz-Institut für Organische Katalyse an der Universität Rostock e V Buchbinderstrasse 5-6, 18055 Rostock, Germany.
Zapf
Alexander
A
Jackstell
Ralf
R
Harkal
Surendra
S
Riermeier
Thomas
T
Monsees
Axel
A
Dingerdissen
Uwe
U
Beller
Matthias
M