Stereoselective Alkylation of Indole with 5-Arylidene-Meldrum’s Acids in the Presence of Organocatalysts - Publication - Bridge of Knowledge

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Stereoselective Alkylation of Indole with 5-Arylidene-Meldrum’s Acids in the Presence of Organocatalysts

Abstract

Background: Indole motif is frequently present in biologically active compounds. Enantiomerically pure or enriched 2,2-dimethyl-5-(aryl(1H-indol-3-yl)methyl)-1,3-dioxane-4,6-diones can be considered as a convenient starting point for the synthesis of a indole ring fused with cyclic ketones with biological activity. Preparation of chiral 2,2-dimethyl-5-(aryl(1H-indol-3-yl)methyl)-1,3-dioxane- 4,6-diones requires the reaction of indole with 2,2-dimethyl-5-arylidene-1,3-dioxane-4,6-diones in the presence of chiral catalysts or other source of chiral induction. Methods: Enantioselective Friedel-Crafts alkylation of indole has been performed with 2,2-dimethyl-5- arylidene-1,3-dioxane-4,6-diones in the presence of organocatalysts to give 5-((1H-indol-3- yl)(aryl)methyl)-2,2-dimethyl-1,3-dioxane-4,6-diones. Broad scope of organocatalysts as well as various temperatures and solvents used for the reaction were tested. Results: 2,2-Dimethyl-5-(aryl(1H-indol-3-yl)methyl)-1,3-dioxane-4,6-diones were obtained with quantitative yield and enantiomeric ratio 1:3 using thiourea organocatalyst. Also a new spectroscopic method for discrimination of 5-((1H-indol-3-yl)(aryl)methyl)-2,2-dimethyl-1,3-dioxane-4,6-diones enantiomers was developed. Conclusion: Enantioselective Friedel-Crafts alkylation of indole has been developed. In the presence of thiourea catalysts, 2,2-dimethyl-5-arylidene-1,3-dioxane-4,6-diones react with indole to give 2,2- dimethyl-5-(aryl(1H-indol-3-yl)methyl)-1,3-dioxane-4,6-diones with good yields and reasonable ee.

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Category:
Articles
Type:
artykuł w czasopiśmie wyróżnionym w JCR
Published in:
LETTERS IN ORGANIC CHEMISTRY no. 15, pages 883 - 890,
ISSN: 1570-1786
Language:
English
Publication year:
2018
Bibliographic description:
Makowiec S., Janikowska K., Zakaszewska A., Najda-Mocarska E.: Stereoselective Alkylation of Indole with 5-Arylidene-Meldrum’s Acids in the Presence of Organocatalysts// LETTERS IN ORGANIC CHEMISTRY. -Vol. 15, nr. 10 (2018), s.883-890
DOI:
Digital Object Identifier (open in new tab) 10.2174/1570178615666180503150327
Sources of funding:
Verified by:
Gdańsk University of Technology

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