Collect. Czech. Chem. Commun.
1996, 61, 1805-1814
https://doi.org/10.1135/cccc19961805
On the Stereoselectivity of the (-)-Dimenthyl Malonate Addition to α,β-Unsaturated Ketones
Ľubomír Šeboa, Juraj Alföldib, Grety Rihsc and Štefan Tomaa
a Department of Organic Chemistry, Comenius University, 842 15 Bratislava, Slovak Republic
b Institute of Chemistry, Slovak Academy of Sciences, 842 15 Bratislava, Slovak Republic
c CIBA-GEIGY Co., CH-4002 Basel, Switzerland
Abstract
The Michael addition of (-)-dimenthyl malonate to eight α,β-unsaturated ketones has been studied. The ratio of diastereomers was calculated on the basis of the 1H NMR spectra of the crude reaction products. The diastereomer excess varied from 10 to 50%, depending on the structure of the starting enone. The pure diastereomer produced by addition of (-)-dimenthyl malonate to 2-benzylidene-1,4-indandione was isolated by repeated crystallization. X-ray analysis has shown that the isomer is (-)-dimenthyl (R)-2-[1-(1,3-dioxoindan-2-yl)-1-phenylmethyl]malonate (5a). The predominating diastereomers of (-)-dimenthyl(3-ferrocenyl-3-oxophenylpropyl)malonate (1a) and (-)-dimenthyl-2-(1-(1,3-dioxo[3]ferrocenophan-2-yl)-1-phenyl malonate (6a) were also isolated in pure state by careful crystallization.
Keywords: Michael addition; (-)-Dimenthyl malonate; Enones.
