Chiral Alkaline Earth Metal Complexes in Asymmetric Catalysis

Abstract

Alkaline earth metal catalysis for asymmetric reactions is a hot topic from the viewpoint of green sustainable chemistry. The stable alkaline earth metals, calcium (Ca), strontium (Sr), and barium (Ba) are abundant in the Earth’s crust, and their strong Brønsted basicity and mild Lewis acidity are useful for construction of alkaline earth metal complexes as chiral catalysts. In this chapter, the development of chiral alkaline earth metal catalysts for catalytic asymmetric reactions is described. The chiral alkaline earth metal complexes are categorized into three types of complexes, types I–III, by coordination modes, and those complexes successfully promoted many types of reactions in acid–base catalysis with high enantioselectivities.