Air-stable phosphine oxides as preligands for catalytic activation reactions of C-Cl, C-F, and C-H bonds*
Lutz Ackermann, Robert Born, Julia H. Spatz, Andreas Althammer, and Christian J. Gschrei
Ludwig-Maximilians-Universität München, Department Chemie und Biochemie, Butenandtstrasse 5-13, Haus F, 81377 München, Germany
Abstract: Studies on the use of easily accessible heteroatom-substituted secondary phosphine oxides as preligands for cross-coupling reactions are described. These air-stable sterically hindered phosphine oxides allow for efficient palladium-catalyzed Suzuki- and nickel-catalyzed Kumada-coupling reactions using electronically deactivated aryl chlorides. In addition, they enable nickel-catalyzed coupling reactions of magnesium organyls with aryl fluorides at ambient temperature, and ruthenium-catalyzed coupling reactions of aryl chlorides via C-H bond activation. Finally, the application of modular diamino phosphine chlorides as preligands for a variety of transition-metal-catalyzed C-C and C-N bond formation reactions employing electron-rich aryl chlorides is presented.
Keywords: secondary phosphine oxide; cross-coupling; C-H bond activation; ruthenium; nickel; palladium.
*Pure Appl. Chem. 78, 197-523. An issue of reviews and research papers based on lectures presented at the 13th IUPAC International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis (OMCOS-13), Geneva, Switzerland, 17-21 July 2005.