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NHC-catalyzed reactions of aryloxyacetaldehydes: a domino elimination/conjugate addition/acylation process for the synthesis of substituted coumarins.

ABSTRACT: N-heterocyclic carbenes (NHCs) catalyze a domino Michael addition/acylation reaction to form 3,4-dihydrocoumarins. The reaction proceeds through addition of the NHC to an aryloxyaldehyde followed by elimination of a phenoxide leaving group, generating an enol intermediate. This transient nucleophile generated in situ performs a 1,4-addition onto a conjugate acceptor, and the carbene catalyst is regenerated upon acylation of the phenoxide anion resulting in formation of 3,4-dihydrocoumarins.

SUBMITTER: Phillips EM

PROVIDER: S-EPMC2640423 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature

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NHC-catalyzed reactions of aryloxyacetaldehydes: a domino elimination/conjugate addition/acylation process for the synthesis of substituted coumarins.

Phillips Eric M EM Wadamoto Manabu M Roth Howard S HS Ott Andrew W AW Scheidt Karl A KA

Organic letters 20090101 1

N-heterocyclic carbenes (NHCs) catalyze a domino Michael addition/acylation reaction to form 3,4-dihydrocoumarins. The reaction proceeds through addition of the NHC to an aryloxyaldehyde followed by elimination of a phenoxide leaving group, generating an enol intermediate. This transient nucleophile generated in situ performs a 1,4-addition onto a conjugate acceptor, and the carbene catalyst is regenerated upon acylation of the phenoxide anion resulting in formation of 3,4-dihydrocoumarins. ...[more]

PMID: 19049403

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