
%0 Journal Article
%A Brinkworth, Craig 
%A Rozek, Tomas 
%A Bowie, John H. 
%A Skelton, Brian W. 
%A White, Allan H. 
%T Angucyclinones Related to Ochromycinone. IV. The Structures and Reactions of Unusual Diels-Alder Adducts Formed from Maleic Anhydride and Racemic 5,5-Dimethyl-3-vinylcyclohex-2-en-1-ol
%J Australian Journal of Chemistry
%D 2000/07/27
%V 53
%N 5
%P 403-409
%K Diels&#8211;Alder reaction; oxidation; synthesis; X-ray crystal structure.
%R https://doi.org/10.1071/CH00034
%U https://www.publish.csiro.au/paper/CH00034 
%X The Diels&#8211;Alder reaction between maleic anhydride and racemic 5,5-dimethyl-3-vinylcyclohex-2-en-1-ol gives two racemic diastereomers, the major product (2a,S,3R,8aS,8bR)-7,7-dimethyl-2-oxo-2a,3,4,6,7,8,8a,8b-octahydro-2H-benzo&#91;cd&#93;isobenzofuran-3-carboxylic acid (63% yield), and the minor product (2aR,3S,8aS,8bS)-7,7-dimethyl-2-oxo-2a,3,4,6,7,8,8a,8b-octahydro-2H-benzo&#91;cd&#93;isobenzofuran-3-carboxylic acid (9%). Epoxidation of the major product gives racemic (1aS,3R,3aS,5aR,8aS,8bR)-7,7-dimethyl-4 oxoperhydro-benzo&#91;cd&#93;oxireno&#91;2,3-e&#93;isobenzofuran-3-carboxylic acid in 81% yield, while opening of the epoxide ring gave the trans diol (2aS,3R,5S,5aR,8aR,8bR)-5,5a-dihydroxy-7,7-dimethyl-2-oxoperhydrobenzo&#91;cd&#93;isobenzofuran-3-carboxylic acid in 58% yield. Treatment of the major Diels&#8211;Alder product with osmium tetraoxide gave the cis diol (2aS,3R,5S,5aR,8aS,8bR)-5,5a-dihydroxy-7,7-dimethyl-2-oxoperhydrobenzo&#91;cd&#93;isobenzofuran-3-carboxylic acid in 86% yield. The structures of four products were confirmed by X-ray and n.m.r. methods. None of the products exhibit anticancer activity. 
