Helical Multi‐Coordination Anion‐Binding Catalysts for the Highly Enantioselective Dearomatization of Pyrylium Derivatives |
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Authors: | Theresa Fischer,Julia Bamberger,Melania G mez‐Martí nez,Dariusz G. Piekarski,Olga Garcí a Manche o |
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Affiliation: | Theresa Fischer,Julia Bamberger,Melania Gómez‐Martínez,Dariusz G. Piekarski,Olga García Mancheño |
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Abstract: | A general and highly enantioselective synthesis of oxygen heterocycles from readily available in situ generated pyrylium derivatives has been realized by embracing a multi‐coordination approach with helical anion‐binding tetrakistriazole catalysts. The high activity of the tetrakistriazole (TetraTri) catalysts, with distinct confined anion‐binding pockets, allows for remarkably low catalyst loadings (down to 0.05 mol %), while providing a simple access to chiral chromanones and dihydropyrones in high enantioselectivities (up to 98:2 e.r.). Moreover, experimental and theoretical studies provide new insights into the hydrogen‐donor ability and key binding interactions of the TetraTri catalysts and its host:guest complexes, suggesting the formation of a 1:3 species. |
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Keywords: | anion binding asymmetric catalysis catalyst design chiral triazoles pyrylium salts |
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