Syntheses of Diterpenoid Alkaloid Intermediates

Ghatak and Chakrabarty have published a full report of their synthesis of (130) and (131) via the dicarboxylic acids (132) and (133). The tetracyclic acetylamine 

Dutta et al have also reported a synthesis of the diacid (132) and its methoxy-analogue (133). These intermediates were prepared from the oxo-acids (135) and (136), respectively, in thirteen steps. However, considerably different experimental conditions from those used for the synthesis of the model diacid (132) were required in several steps in the synthesis of the methoxy-series. 

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