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 towards 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.
Organocatalysts are useful for asymmetric synthesis to achieve desired enantiomeric and/or diastereomeric form of compounds, particularly important in pharmaceutical syntheses. Reactions using organocatalysts typically proceeds 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.