Diastereo- and Enantioselective Synthesis of 9-Aryl-1-vinyl-tetrahydro-β-carbolines via Brønsted Acid-Catalyzed Pictet-Spengler Reaction.
Reported herein is a stereoselective synthesis of 9-aryl-1-vinyl-tetrahydro-β-carbolines via a Pictet-Spengler reaction. This reaction proceeds via Brønsted acid-catalyzed cyclization of N-indole-tethered allenamides with >20:1 dr under mild conditions, while chiral phosphoric acid catalysis installs the C-N axial chir...