SPECIALTOPIC	Synthesis 2008: 1965-1970   DOI: 10.1055/s-2008-1067095
© Georg Thieme Verlag Stuttgart · New York
Sterically Demanding, Zwitterionic Trialkylphosphonium Sulfonates as Air-Stable Ligand Precursors for Efficient Palladium-Catalyzed Cross-Couplings of Aryl Bromides and Chlorides
William S. Brown, D'Ariel D. Boykin, M. Quentin Sonnier Jr., William D. Clark, Fallon V. Brown, Kevin H. Shaughnessy*
Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487-0336, USA Fax: +1(205)3489104; e-Mail: kshaughn@bama.ua.edu;
Received 15 February 2008

Abstract

3-(Di-tert-butylphosphonium)propane sulfonate (DTBPPS) and 3-(diadamantylphosphonium)propane sulfonate (DAPPS) are air-stable pre-ligands for aqueous-phase palladium-catalyzed cross-coupling reactions. Both DTBPPS and DAPPS were found to give active catalysts for the Sonogashira coupling of aryl bromides at room temperature and 4-chloroanisole at 80 °C. These ligands also gave effective catalysts for the aqueous-phase Suzuki coupling of aryl bromides at room temperature.

Key words

palladium - cross-coupling - ligands - aqueous-phase catalysis - aryl halides