Palladium-catalyzed reactions are versatile methods for carbon-carbon bond formation due to their generality and ability to tolerate a wide range of important organic functional groups. Developing novel Palladium-catalyzed reactions has therefore been of great interest to synthetic chemists for years;The regio- and stereoselective synthesis of tetrasubstituted olefins is a long-pursuing challenge for synthetic chemists. A multi-component reaction route is ideal to generate various tetrasubstituted olefins in a very concise manner and should be highly desirable for applications in combinatorial chemistry. A highly efficient, regio- and stereoselective route to tetrasubstituted olefins has been developed by the Pd-catalyzed three-component reaction of aryl iodides, internal alkynes, and arylboronic acids as described in Chapter 1. By applying the synthetic protocol we have developed, tamoxifen and its derivatives have been successfully prepared in one step with excellent regio- and stereochemical control, employing readily available starting materials;A novel Pd-catalyzed reaction between arylboronic acids and internal alkynes for the synthesis of tetrasubstituted olefins has been successfully developed as described in Chapter 2. Molecular O2 is used as an oxidant and no base is needed for this reaction. A wide variety of tetrasubstituted olefins have been successfully synthesized under our simple and very mild reaction conditions;The activation of nitrile functionality by organopalladium compounds is rather rare and a challenge in Pd chemistry. Using a highly cationic Pd(II) catalyst, a new route to aryl ketones or ketimines has been successfully developed by a novel reaction between arenes and nitriles as described in Chapter 3. A novel reaction between an arylboronic acid and a nitrile has also been successfully developed as a convenient route to aryl ketones;Chromone is an abundant key structure in many natural products. An efficient route to iodochromones has been successfully developed via ICl-induced cyclization as described in Chapter 4. The chemistry is run under very mild conditions and tolerates a wide variety of functional groups. The iodochromones products can be easily transformed to other substituted chromones or polycyclic compounds using organopalladium chemistry.