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

…, M Wadamoto, HS Roth, AW Ott, KA Scheidt

Index: Phillips, Eric M.; Wadamoto, Manabu; Roth, Howard S.; Ott, Andrew W.; Scheidt, Karl A. Organic Letters, 2009 , vol. 11, # 1 p. 105 - 108

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Citation Number: 67

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 ...