Recent advances in Pd-catalyzed asymmetric addition reactions

Addition reactions involving conjugate addition and 1,2-addition of various nucleophiles to unsaturated bonds is one of the most important areas in modern organic chemistry, allowing the direct formation of carbon-carbon or carbon-heteroatom bonds under mild conditions. In comparison with other transition metals, palladium complexes provides high catalytic efficiency, also being inexpensive when compared with rhodium. The Pd-catalyzed asymmetric addition reactions have become a common tool for the construction of optically active compounds as well as biologically active molecules and natural products. In the past decades, many novel and efficient Pd catalyst systems based on various chiral ligands have been developed and high stereoinduction could be achieved with both nucleophilic and electrophilic reactions partners. The asymmetric conjugate additions of different types of nucleophiles, such as boronic acids, diphenylphosphine, aryltriethylsiloxanes and amines, to electron-deficient olefins provided a useful strategy to construct carbon stereocenters with highly chemo-, regio- and stereoselectivity. The palladium-catalyzed enantioselective 1,2-addition to various electrophiles, including aldehydes, ketones, aldimines, ketimines, olefins, allenes and cumulenes, have emerged as a powerful approach for the construction of chiral alcohols, amines, allylic compounds, etc. In this chapter, the recent achievements and developments in palladium-catalyzed enantioselective addition processes and synthetic applications are summarized.