Pd–Tetrahydrosalan‐Type Complexes as Catalysts for Sonogashira Couplings in Water: Efficient Greening of the Procedure

• DOI: 10.1002/cssc.201402147
• Publication Date: 2014-07-03T12:30:02Z
• Authors: Krisztina Voronova; Levente Homolya; Antal Udvardy; Attila C. Bényei; Ferenc Joó
• Keywords: Sonogashira coupling; Aqueous medium; Filtration (mathematics); Coupling reaction

Abstract New sulfonated tetrahydrosalen‐type ligands and their water‐soluble palladium(II) complexes have been synthesized. The catalyze the Sonogashira coupling (23 examples) of various aryl halides (including chloroarenes) with terminal alkynes, good to excellent conversions under mild conditions (80 °C, air, no Cu I cocatalyst) in aqueous–organic mixtures turnover frequencies up 2790 h −1 . Under optimized reaction minimize environmental contamination, diphenylacetylenes can be isolated 76–98 % yield. aqueous catalyst solution recycled four times decreasing activity; however, yields between 93 98 still achieved extended times. Several water‐insoluble products yield by simple filtration purification washing water; this method is used, for first time, type CC procedure.