Stereoselective deuteriation at carbon 2 of the gibberellins

Abstract

Various routes are described for the preparation of 2α- and 2β-deuteriated gibberellins. The stereoselective preparation of gibberellins A₄ and A₉, containing 0.8 deuterium atoms per molecule of which 90% was located at the 2α-position, was achieved via 2β-iodo-3-oxogibberellin A₄. An improved incorporation (0.9 deuterium atoms per molecule) was obtained via 2β-bromo-3-oxogibberellin A₄, the preparation of which, from 2β-iodo-3-oxogibberellin A₄, is discussed.