Chiral Borane-Based Lewis Acids for Metal Free Hydrogenations

Abstract

The unquenched reactivity of strong Lewis acids in the presence of Lewis bases in solution, the so-called frustrated Lewis pairs (FLP), has led to the discovery of the metal-free activations, whereas the FLP-mediated hydrogen activation is the most prominent. So far, the metal-free hydrogenation is the most studied application of FLP chemistry and highly efficient methodologies for a number of unsaturated substrates have been developed. This chapter starts with a brief introduction to frustrated Lewis pair chemistry. The second part focuses on the synthetic challenges of chiral borane-derived Lewis acids for asymmetric transformations. The last part gives a state-of-the-art summary of asymmetric transformations using chiral FLPs.