Structural Design for Molecular Catalysts
This chapter presents the success of different synthesis strategies for molecular catalysts or catalytic active ligands from organometallic, organic non-metallic, and biological groups. In comparison with purely organic compounds, organometallic compounds show unique chemical properties, including structural diversity, variety of available interactions, and possibility of ligand exchange. Designing a protein to accommodate a non-native transition metal complex can broaden the scope of enzymatic transformations and enhance the activity/selectivity for small-molecule catalysis. Through the design of Bronsted acids with a variety of structures and activation mechanisms, they can be tuned to support high yield and enantioselectivity in a variety of reactions, including Strecker and Mannich reactions, Diels–Alder reaction, hydrogenations and Michael additions. J. N. Johnston et al. designed a metal-free organocatalyst based on a properly balanced Bronsted acid/base bifunctional catalyst, which may bring the virtues of minimalism for the formation of C–O bonds.