Chapter 5: Proline as an Asymmetric Organocatalyst

Asymmetric proline catalysis is a well-established tool in organic synthesis. This chapter outlines and summarises developed methods and applications. The traditional use of proline in asymmetric aldol, Michael and Mannich-type reactions is described; however, the primary focus of this chapter is to survey more recent applications including α-functionalisations, cycloadditions and the formation and ring opening of cyclopropanes and epoxides. The chapter reviews various methodologies and puts them into perspective regarding their applicability as sustainable and ideally scalable processes in organic synthesis. The ongoing challenges of proline catalysis, and the ultimate task to find a way into nonacademic process applications, are addressed with appropriate examples.