Asymmetric Steering of the Pictet‐Spengler Reaction by Means of Amino Acid Esters as Chiral Auxiliary Groups.
TL;DR: Zusammenfassung N-β-(3-Indolyl)ethyl amino acid esters and differently substituted aromatic aldehydes in the presence of acetic acid form iminium intermediates which at 6°C to 40°C undergo Pictet-Spengler cyclizations to give tetrahydro-β-carbolines with diastereomer ratios up to 98.5:1 as discussed by the authors.
Abstract: Zusammenfassung N-β-(3-Indolyl)ethyl amino acid esters and differently substituted aromatic aldehydes in the presence of acetic acid form iminium intermediates which at 6°C to 40°C undergo Pictet-Spengler cyclizations to give tetrahydro-β-carbolines with diastereomer ratios up to 98.5:1.5. The chiral auxiliary group is removed from the heterocycles by employing a retro Strecker reaction as the key transformation.
References
More filters
TL;DR: Zusammenfassung N-β-(3-Indolyl)ethyl amino acid esters and differently substituted aromatic aldehydes in the presence of acetic acid form iminium intermediates which at 6°C to 40°C undergo Pictet-Spengler cyclizations to give tetrahydro-β-carbolines with diastereomer ratios up to 985:15 as discussed by the authors.
42 citations