Chapter 7: Prolinols and Their Carbon Ethers as Asymmetric Organocatalysts

Commercially or readily available prolinols and their carbon ethers have been successfully employed as versatile catalysts in a variety of enantioselective transformations such as Michael addition reactions, epoxidation and cyclopropanation of electron-deficient alkenes, aldol reactions, cycloadditions, desymmetrisation reactions, α-sulfenylation and reduction of carbonyl compounds. The striking feature of the catalytic behaviour of prolinols is their unique ability to serve as promoters in both noncovalent and covalent activation modes of the reagents. To make methodologies more cost effective and environmentally friendly, some efforts have been directed to immobilise the prolinol scaffold onto polymers or develop fluorinated derivatives suitable for recycling coupled with the use of water and alcohols as solvents or cosolvents.