5-(Pyrrolidin-2-yl)tetrazole-Catalyzed Aldol and Mannich Reactions: Acceleration and Lower Catalyst Loading in a Continuous-Flow Reactor

摘要

Synthetic transformations involving chiral catalysts are attractive owing to their efficiency and atom economy. Organocatalysis is becoming increasingly popular as an alternative to catalysis by metal complexes. Proline and some of its derivatives catalyze aldol reactions with selectiv-ities typically observed only with enzymes. Still, proline-catalyzed asymmetric aldol reactions and other transformations requiring amine catalysts suffer from long reaction times (sometimes several days) and high catalyst loading (typically 20-30 mol). Accelerating organocatalytic reactions while at the same time lowering catalyst loadings would be an important step forward for this rapidly developing field.