Enantioselective Annulation Using Nazarov Reagent: Synthesis of (+)-Preoleanatetraene
作者:Alejandro F. Barrero、Simeón Arseniyadis、José F. Moral、M. Mar Herrador、Antonio Rosellón
DOI:10.1055/s-2005-864798
日期:——
The enantioselective synthesis of preoleanatetraene (1) has been accomplished via a convergent approach of two C-15 synthons. The key step of this synthesis has been an interesting enantioselective variant of the Robinson annulation using the Nazarov reagent and a chiral enamine to obtain the bicyclic moiety A. This asymmetric methodology opens the access to other irregular triterpene skeletons whose biogenetic implication should not be underestimated.