GIBBERELLINE-LXII SYNTHESE VON 7-DESOXYGENIERTEN GIBBERELLIN-A3-VERBINDUNGEN

Article abstract of DOI:10.1016/0040-4020(80)87025-6

Reaction sequences leading to GA₃ derivatives with stepwise deoxygenated position 7 have been reported.From four different methods studied for the synthesis of GA₃-7-alcohols the direct NaBH4-reduction of the anhydrides 5a and 5b has been found to be optimal leading in good yields to 3 and 9, respectively.Oxidation of 3 with the N-chlorosuccinimide-dimethylsulfide complex or pyridinium chlorochromate followed by deacetylation afforded the GA₃-7-aldehyde (16).-The partial synthesis of 6β-methyl-7-nor-GA₃ (20) has been realized starting from 3 via the iodinemethyl compound 18 and its reduction with (C2H5)3SnH or Na2 to 19 and subsequent saponification.-The structures of the new gibberellin derivatives were determined on the basis of IR, (1)H-NMR and MS data.