Syntheses of Angucyclinones Related to Ochromycinone. Part 3. 11-Hydroxy Isomers and Some Reduced Analogues
Date
1999
Authors
Rozek, T.
Taylor, D.
Tiekink, E.
Bowie, J.
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Advisors
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Journal article
Citation
Australian Journal of Chemistry, 1999; 52(2):129-135
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Abstract
<jats:p>The boron triacetate assisted Diels Alder reaction between racemic 5,5-dimethyl-3-vinylcyclohex- 2-enyl acetate and 5-hydroxynaphthoquinone yields the racemic 11-hydroxy-3,3-dimethyl-7,12-dioxo- 1,2,3,4,6,6a,7,12,12a,12b-decahydrobenzo[ a ]anthracen-1-yl acetate as the sole stereoisomer by regio- and stereo-selective cis endo addition. Aromatization of the Diels Alder adduct followed by hydrolysis of the acetate and oxidation of the resultant 1-hydroxy group gives the target angucyclinone, 11-hydroxy-3,3-dimethyl-1,2,3,4,7,12-hexahydrobenzo[ a ]anthracene-1,7,12-trione, in an overall yield of 37% from 5-hydroxynaphthoquinone. The regio- and stereo-selectivity of the Diels Alder addition is confirmed by a combination of 13C n.m.r. spectroscopy and X-ray crystallography.</jats:p>