Organocatalysis--after the gold rush.

The use of secondary amines as asymmetric catalysts in transformations of carbonyl compounds has seen tremendous development in recent years. Going from sporadic reports of selected reactions, aminocatalysis can now be considered as one of the methods of choice for many asymmetric functionalizations of carbonyl compounds--primarily of aldehydes and ketones. These functionalizations have been published at a breathtaking pace over the last few years--during the "golden age" and "gold rush" of organocatalysis. This tutorial review will firstly sketch the basic developments in organocatalysis, focussing especially on the use of secondary amines as catalysts for the functionalization of aldehydes and alpha,beta-unsaturated aldehydes, with emphasis on the mechanisms of the transformations and, secondly, outline recent trends within central areas of this research topic. Lastly, we will present our guesses as to where new developments might take organocatalysis in the years to come.