Axially Chiral Amidinium Ions as Inducers of Enantioselectivity in Diels−Alder Reactions
- 1 January 2000
- journal article
- letter
- Published by American Chemical Society (ACS) in Organic Letters
- Vol. 2 (2) , 179-181
- https://doi.org/10.1021/ol991276i
Abstract
Enantioselective catalysis of Diels−Alder reactions is mostly achieved by coordinating the dienophile to relatively strong chiral Lewis acids. Here we report on a novel approach employing the hydrogen-bond-mediated association of dienophiles to chiral host molecules. In a reaction forming the steroid skeleton of norgestrel, chiral amidinium ions induce 5:ent-5 ratios of up to 2.5:1. Improved and simplified amidinium catalysts may become interesting candidates to perform stereoselective transformations.Keywords
This publication has 5 references indexed in Scilit:
- Synthesis of a Chiral Receptor Molecule with Converging Amidinium and Hydroxy GroupsSynlett, 1999
- Total Synthesis with a Chirogenic Opening Move Demonstrated on Steroids with Estrane or 18a-Homoestrane SkeletonHelvetica Chimica Acta, 1995
- Axial-chirale Amidinium-Ionen mit Biarylgerüst: ein neuer Strukturtyp für die Wirt-Gast-ChemieAngewandte Chemie, 1994
- Condensation of 1-Vinyl-6-methoxy-3,4-dihydronaphthalene and 3-Methyl-3-cyclopentene-1,2-dione. Structure of Dane's AdductJournal of the American Chemical Society, 1956
- Synthesen in der hydroaromatischen Reihe. VI. Die Addition von 1‐Vinyl‐6‐methoxy‐3,4‐dihydro‐naphtalin an Δ1‐Cyclopentenon und an Δ1‐4,4′‐Dibrom‐cyclopenten‐dion‐3,5European Journal of Organic Chemistry, 1939