Abstract
Lanthanide (Ln) metals are strong reducing agents (E0(Ln3+/Ln0)≈−2.3 V vs. NHE) which can be applied in various manners in organic synthesis. While samarium and ytterbium have been employed for more than 50 years, the last 20 years have seen the emergence of synthetic applications using other metals, such as lanthanum, cerium, praseodymium, neodymium or dysprosium. The large electron reservoir of lanthanide metals, the Lewis acidic character of the Ln3+ ions and their intermediate electronegativity compared to lithium or magnesium can provide unique reactivity patterns. This review provides an overview on the potential of these metals for synthetic organic chemistry in the following areas: 1) for Grignard type reactivity and radical generation, 2) in reduction chemistry involving carbonyl compounds and dehalogenation reactions and 3) in combination with transition metals.