ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Michael additions of 1,3-cycloalkanediones to dimethyl acetylenedicarboxylate

P. Hrnčiar, V. Padychová, and J. Šraga

Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, CS-842 15 Bratislava

Abstract: Michael additions of 1,3-cyclopentanedione, 1,3-cyclohexanedione, 5,5-dimethyl-l,3-cyclohexanedione, and 1,3-cycloheptanedione to dimethyl acetylenedicarboxylate catalyzed by CH₃ONa, piperidine or KF/Al₂0₃ were performed. There was found out that, like additions to a double bond, the Michael addition to a triple bond takes place successfully under KF/Al₂0₃ catalysis. The influence of a catalyst upon cis/trans ratio of the addition product was investigated; catalysis by KF/Al₂0₃  prefers the cis addition to the greater extent compared to catalysis by sodium methoxide. It was found out that the addition of 1,3-cycloheptanedione to dimethyl acetylenedicar­boxylate exhibits a more complex course of the reaction; in the case of 1,3-cyclopentanedione, the product of the trans addition does not form 2H-pyrone ring, while a derivative of 2H-pyrone is the product of trans addition of 1,3-cyclohexanediones.

Full paper in Portable Document Format: 431a87.pdf

Chemical Papers 43 (1) 87–95 (1989)