Stereochemistry of cyclic compounds communication II. Stereochemistry of 1,2,3,5,6,7,8,8a-octahydro-1,2-naphthalenedicarboxylic acids

Summary

• 1. By the addition of methanol to the isomeric cis anhydrides (1) and (X) and by the partial hydrolysis of the cis diesters (III) and (XII1), all four of the isomeric monoesters (II), (IV), (XI), and (XIV) of syn-cis- and anti -cis-1,2,3,5,6,Z,8,8a-octahydro-1,2-naphthalenedicarboxylic acids were prepared.

• 2. It was shown that the isomerization of the monoesters (IV) and (XI) by means of sodium methoxide gives the anti-trans acid (XVI), whereas similar treatment of. the monoesters (11) and (XIV) gives the isomeric syn-trans acid (XVID. This proves the configurations of the isomeric cis anhydrides (1) and (X) as epimers with respect to the hydrogen at C-8a.

• 3. 1-Vinyl-l. cyclohexene was condensed with fumaric ester, and an 88% yield of a mixture of equal amounts of the anti-trans and syn-trans diesters (XIX) and (XXI) was obtained.

• 4. An examination of molecular models has enabled us to explain the spatial configurations of all four isomeric 1,2,3,5,6,7,8,8a-octahydro-1,2-naphthalenedicarboxylic acids and some of their reactions.