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Chiral N-heterocyclic carbene-catalyzed generation of ester enolate equivalents from {alpha},{beta}-unsaturated aldehydes for enantioselective Diels-Alder reactions



Chiral N-heterocyclic carbene-catalyzed generation of ester enolate equivalents from {alpha},{beta}-unsaturated aldehydes for enantioselective Diels-Alder reactions



Proceedings of the National Academy of Sciences of the United States of America 107(48): 20661-5



The catalytic generation of chiral ester enolate equivalents from α,β-unsaturated aldehydes with chiral N-hetereocyclic carbene catalysts makes possible highly enantioselective hetero-Diels-Alder reactions. The reactions proceed under simple, mild conditions with both aliphatic and aromatic substituted enals as substrates. Previous attempts to employ these starting materials as enolate precursors gave structurally different products via catalytically generated homoenolate equivalents. Critical to the success of the enolate generation was the strength of the catalytic base used to generate the active N-heterocyclic carbene catalyst. To complement these studies, we have investigated the enolate structure using computational methods and find that it prefers conformations perpendicular to the triazolium core.

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Accession: 052063371

Download citation: RISBibTeXText

PMID: 20974930

DOI: 10.1073/pnas.1007469107


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