Synthesis of α-Methylenecarbonyl Compounds: An Unexpected Product from the Mannich Reaction On 2-Carbomethoxycyclohexanone

Abstract

During a study of a general synthesis of α-methylenecarbonyl compounds,¹ we investigated the Mannich reaction of 2-carbomethoxycyclohexanone with formaldehyde and various secondary amines. The unexpected formation of 6-methylene-2-carbomethoxycyclohexanone, existing mainly in the enol form, as the only isolable product is the subject of this report.