Total Synthesis of the Galbulimima Alkaloids Himandravine and GB17 Using Biomimetic Diels-Alder Reactions of Double Diene Precursors.

ABSTRACT: The enantioselective total syntheses of himandravine and GB17 were completed through a common biomimetic strategy involving Diels-Alder reactions of unusual double diene containing linear precursors. The double diene precursors, containing or lacking a C12 substituent as required to produce GB17 or himandravine, respectively, were found to undergo Diels-Alder reactions to afford mixtures of regioisomeric cycloadducts that map onto the alternative carbocyclic frameworks of both himandravine and GB17. Computational investigations revealed that these Diels-Alder reactions proceed via transition state structures of similar energy that have a high degree of bispericyclic character and that the low levels of regioselectivity observed in the reactions are a consequence of competing orbital intera

SUBMITTER: Larson RT 

PROVIDER: S-EPMC4612511 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature