Determination of Stereochemistry at C-16 of Dihydrogibberellin A₁ Methyl Ester (Methyl Tetrahydrogibberellate) and Its 16-Epimer

Abstract

Stereochemistry at C-16 of dihydrogibberellin A₁ methyl ester (methyl tetrahydrogib-berellate, III) and its 16-epimer was elucidated. NMR nalysis employing a shift reagent, Eu(thd)₃ or Eu(fod)₃, was found to be very effective for settling this stereochemical problem.