Quinone epoxides. Part VI. The synthesis and stereochemistry of terremutin

Abstract

Reduction of (±)-terreic acid (I) with sodium borohydride gives (±)-terremutin (IV) and (±)-epiterremutin (III) as minor and major products respectively. Analysis of the n.m.r. spectra of these diastereoisomers and the adducts formed by treating them with pyridine clearly indicates that, contrary to an earlier proposal, a trans-relationship exists between the secondary hydroxy-group and the epoxide ring in terremutin.