Catalytic Enantioselective Pictet‐Spengler Reaction of α‐Ketoamides Catalyzed by a Single H‐Bond Donor Organocatalyst

The asymmetric Pictet–Spengler reaction (PSR) with aldehydes is well known. However, PSR involving ketones as electrophilic partners far-less developed. We report herein the first examples of catalytic enantioselective tryptamines α-ketoamides. A new class easily accessible prolyl-urea organocatalysts bearing a single H-bond donor function catalyzes title to afford 1,1-disubstituted tetrahydro-β-carbolines in excellent yields and enantioselectivities. kinetic isotope effect using C2-deuterium-labelled tryptamine indicates that rearomatization pentahydro-β-carbolinium ion intermediate might be rate- enantioselectivity-determining step.