KCS

Palladium catalyzed carbon-carbon bond formation reactions have been widely used in organic synthesis. In contrast to the well-developed phosphine ligands, phosphite ligands have received relatively little attention, despite the fact that phosphites have an advantage in terms of their stability toward air and moisture. Therefore, our attention was drawn to those of them, which have sterically hindered groups, so that they can be employed as ligands. Herein, we report on the subjects of Hiyama coupling, homocoupling, dehalogenation and aminocarbonylation using phosphites as ligands. In addition, decarboxylative coupling of sp-sp2 carbons is possible by palladium-catalyst. Employing propiolic acid (1) as a difunctional alkyne, and using the consecutive reactions of the Sonogashira reaction and the decarboxylative coupling, unsymmetrically substituted diaryl alkynes were obtained in moderate to good yield.