Trapping enols of esters and lactones with diazomethane

A series of regioisomeric ketene-O,O-dialkyl acetals were prepared from ambident β-dicarbonylfuroindoles by trapping the enol tautomers of esters and lactones with diazomethane. Definitive structural characterization was accomplished by X-ray crystal structure determination on a ketene-O,O-dimethyl acetal (R = Me).

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