Substitution reactions of the 3-epimeric methanesulphonates of methyl gibberellate

Abstract

Whereas displacement of the 3β-(axial)-methylsulphonyloxy group from methyl gibberellate with lithium chloride or buffered aqueous acetone proceeds predominantly with syn rearrangement to afford the 1β-chloro- or 1β-hydroxy-gibberellin, the corresponding 3α-(equatorial) epimer reacts with simple inversion of configuration. This affords on the one hand a facile route to the 1-hydroxygibberellins and, on the other, a means of labelling gibberellins at C-3.