N‐Heterocyclic Carbene Catalyzed Formal [3+2] Annulation Reaction of Enals: An Efficient Enantioselective Access to Spiro‐Heterocycles |
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| Authors: | Dr Chang Guo Michael Schedler Constantin G Daniliuc Prof Dr Frank Glorius |
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| Institution: | Westf?lische Wilhelms‐Universit?t Münster, Organisch‐Chemisches Institut, Corrensstrasse 40, 48149 Münster (Germany) http://www.uni‐muenster.de/Chemie.oc/glorius/ |
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| Abstract: | A highly enantioselective N‐heterocyclic carbene (NHC) catalyzed formal 3+2] annulation of α,β‐unsaturated aldehydes with azaaurones or aurone generating spiro‐heterocycles has been developed. The protocol represents a unique NHC‐activation‐based approach to access spiro‐heterocyclic derivatives bearing a quaternary stereogenic center with high optical purity (up to 95 % ee). |
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| Keywords: | asymmetric synthesis enals N‐heterocyclic carbenes organocatalysis spiro‐heterocycles |
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