Merging Organocatalysis and Gold Catalysis: Enantioselective Synthesis of Tetracyclic Indole Derivatives through a Sequential Double Friedel–Crafts Type Reaction
✍ Scribed by Charles C. J. Loh; Jan Badorrek; Prof. Dr. Gerhard Raabe; Prof. Dr. Dieter Enders
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 450 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
D. Enders et al.
stirred for a further 10 min. The corresponding nitrostyrene alkyne 5 a-c (0.8 mmol, 1 equiv), dissolved in CHCl 3 (4 mL), was then added and the reaction mixture was cooled to À30 8C. Indole 4 a-d (1.2 mmol, 1.5 equiv), dissolved in CHCl 3 (2 mL), was subsequently added and the reaction was monitored by TLC, until full conversion of the first tandem step was observed. The reaction was warmed to room temperature over 30 min, and p-TSA (0.6 mmol, 0.75 equiv) and [AuA C H T U N G T R E N N U N G (PPh 3 )]NTf 2 (0.08 mmol, 0.1 equiv) were transferred to the reaction mixture sequentially. The reaction mixture was heated under reflux and monitored by TLC, until no further changes were observed. The product was then directly purified by flash column chromatography.