Oxidative organocatalysed enantioselective coupling of indoles with aldehydes that forms quaternary carbon stereocentres.

Autor: Rezayee NM; Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email: kaj@chem.au.dk., Lauridsen VH; Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email: kaj@chem.au.dk., Næsborg L; Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email: kaj@chem.au.dk., Nguyen TVQ; Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email: kaj@chem.au.dk., Tobiesen HN; Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email: kaj@chem.au.dk., Jørgensen KA; Department of Chemistry , Aarhus University , DK-8000 Aarhus C , Denmark . Email: kaj@chem.au.dk.
Jazyk: angličtina
Zdroj: Chemical science [Chem Sci] 2019 Feb 13; Vol. 10 (12), pp. 3586-3591. Date of Electronic Publication: 2019 Feb 13 (Print Publication: 2019).
DOI: 10.1039/c9sc00196d
Abstrakt: The first organocatalysed, metal-free cross-nucleophile coupling of indoles with α-branched aldehydes forming acyclic stereoselective quaternary carbon centres is presented. Applying an amino acid-derived catalyst with suitable organic oxidants affords the desired enantioenriched indole functionalised products with moderate to excellent yield and enantioselectivity. Two metal-free oxidative protocols employing either DDQ or a sequential approach that uses two organocatalysts to facilitate the use of O 2 as the terminal oxidant are disclosed. These methods are compatible with various indoles ranging from electron-rich to -deficient substituents at the C-2, -5, -6, and -7-positions reacting with a series of different α-branched aldehydes.
Databáze: MEDLINE
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