Highly enantioselective Pictet-Spengler reactions with alpha-ketoamide-derived ketimines: access to an unusual class of quaternary alpha-amino amides.

"Quat's" the story? N-Aryl amides are effective directing/activating groups for chlorosilane Lewis acids. This aspect has been exploited for the development of the first simple and general method for the highly enantioselective Pictet-Spengler reaction of ketimines derived from alpha-ketoamides leading to quaternary alpha-amino acid derivatives (see scheme).