N-Heterocyclic Carbene (NHC)-Catalyzed/Lewis Acid Mediated Conjugate Umpolung of Alkynyl Aldehydes for the Synthesis of Butenolides: A Formal [3+2] Annulation

N-Heterocyclic Carbene (NHC)-Catalyzed/Lewis Acid Mediated Conjugate Umpolung of Alkynyl Aldehydes for the Synthesis of Butenolides: A Formal [3+2] Annulation

Reverse to success! A new formal [3+2] annulation reaction combining alkynyl aldehydes and β,γ‐unsaturated α‐ketoesters has been disclosed by using a NHC‐catalyzed/Lewis acid mediated strategy. This cooperative catalysis strategy first allows the “allenolate” intermediate as a nucleophilic synthon a...

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Veröffentlicht in:Chemistry : a European journal 2013-03, Vol.19 (13), p.4146-4150
Hauptverfasser: Qi, Jing, Xie, Xingang, Han, Runfeng, Ma, Donghui, Yang, Juan, She, Xuegong
Format: Artikel
Sprache:eng
Schlagworte:
Aldehydes
allenolates
Bonding
Chemical reactions
Chemistry
Conjugates
Lewis acid
Lewis acids
N-heterocyclic carbenes
Organic chemistry
organocatalysis
Strategy
Synthesis
umpolung
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Beschreibung
Zusammenfassung:Reverse to success! A new formal [3+2] annulation reaction combining alkynyl aldehydes and β,γ‐unsaturated α‐ketoesters has been disclosed by using a NHC‐catalyzed/Lewis acid mediated strategy. This cooperative catalysis strategy first allows the “allenolate” intermediate as a nucleophilic synthon at the β‐position to react with activated electrophilic reagents by an addition reaction as the key CC bond‐forming step.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.201204386