Palladium--phosphinous acid-catalyzed Sonogashira cross-coupling reactions in water.

A palladium--phosphinous acid-catalyzed Sonogashira cross-coupling reaction that proceeds in water under air atmosphere in the absence of organic co-solvents has been developed. Disubstituted alkynes have been prepared in up to 91% yield by POPd-catalyzed coupling of various aryl halides including chlorides in the presence of tetrabutylammonium bromide and pyrrolidine or NaOH.