Organocatalysis is the use of specific organic molecules that can accelerate chemical reactions via catalytic activation. In contrast to the other two major classes of catalysts, organometallics, and enzymes, organocatalysis does not require the use of metals nor large complex molecules to achieve catalytic activation. Due to their efficiency and selectivity, organocatalysts are of interest in efforts toward sustainable chemistry. Indeed, organocatalysis supports a number of the main tenets of green chemistry, providing for less hazardous syntheses, more energy efficiency, and atom economy.
Asymmetric organocatalysis is useful to achieve desired enantiomeric and/or diastereomeric forms of compounds, particularly important in pharmaceutical syntheses. Reactions using organocatalysts typically proceed via four distinct mechanisms based on whether the catalyst acts as a Lewis acid, Lewis base, Bronsted acid, or Bronsted base. Thus, the scope of organocatalysis is quite broad, influencing many different classes of reactions.