Organocatalytic enantioselective synthesis of dihydronaphthofurans and dihydrobenzofurans: reaction development and insights into stereoselectivity.

Autor: Susam ZD; Middle East Technical University, Department of Chemistry, 06800, Çankaya, Ankara, Turkey. tanyeli@metu.edu.tr., Özcan BD; Middle East Technical University, Department of Chemistry, 06800, Çankaya, Ankara, Turkey. tanyeli@metu.edu.tr., Kurtkaya E; Middle East Technical University, Department of Chemistry, 06800, Çankaya, Ankara, Turkey. tanyeli@metu.edu.tr., Yildirim E; Middle East Technical University, Department of Chemistry, 06800, Çankaya, Ankara, Turkey. tanyeli@metu.edu.tr., Tanyeli C; Middle East Technical University, Department of Chemistry, 06800, Çankaya, Ankara, Turkey. tanyeli@metu.edu.tr.
Jazyk: angličtina
Zdroj: Organic & biomolecular chemistry [Org Biomol Chem] 2022 Nov 16; Vol. 20 (44), pp. 8725-8740. Date of Electronic Publication: 2022 Nov 16.
DOI: 10.1039/d2ob01571d
Abstrakt: Squaramide/cinchona alkaloid-derived bifunctional organocatalysts are in high demand in asymmetric transformations. Bifunctional quinine-derived sterically encumbered squaramide (H-bond donor) organocatalysts were used to catalyze the asymmetric Friedel-Crafts/S N 2 type domino reaction of ( Z )-α-bromonitroalkenes and α/β-naphthols and phenol derivatives to generate enantiomerically enriched dihydronaphthofuran (DHN) and dihydrobenzofuran (DHB) derivatives, respectively. The target adducts were obtained in up to >99% ee under mild conditions with a relatively low catalyst loading (5 mol%) compared to the methods known in the literature. In addition, density functional theory (DFT) calculations were performed to establish a possible outcome, explaining the origin of the stereoselectivity. It was discovered that π-stacked interactions for the trans -conformation in the Friedel-Crafts step are 0.79 kcal mol -1 more stable than the cis -conformation.
Databáze: MEDLINE
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