Diterpenoides. XXI. Hydration of Stereoisomers of Dimethyl 1, 2, 3, 4, 5, 10, 11, 14-Octahydro-4β, 10α-dimethyl-fluorene-4α, 6-dicarboxylate

Abstract

Syntheses of 12- and 13-hydroxy diesters (XIII, XIV, XXI, and XXII) regarded as important intermediates for the formation of D-ring as in gibberellin, were accomplished in the unstable trans-(II) and stable cis-A/B-ring fused isomer (V) by reduction in lithium-liq. ammonia system and then by hydration with mercuric acetate. It is noticeable that 12-hydroxy diester (XX) obtained by epimerization at C-6 of the unstable form (XIII) has the same skeleton as in A- and B-ring of gibberallin A₁₂.