SYNTHESIS OF 3,12-DIHYDROXY-9,15-CYCLOGIBBERELLINS

The methyl esters of 3,11- and 3,12-dihydroxy-9,15-cyclogibberellins h ave been synthesised from the gibberellin GA(7) with a view to determi ning the structure of a gibberellin-like antheridiogen isolated from p rothallia of the fern Anemia phyllitidis, Introduction of an 11 alpha- hydroxyl was effected via S(N)2 substitution of an 11 beta-bromo-9,15- cyclogibberellin while hydroboration of an 11,16-diene provided access to the 3,12-dihydroxy isomers, Structures of the latter compounds wer e confirmed by X-ray crystallography. (C) 1998 Elsevier Science Ltd. A ll rights reserved.