Modular Synthesis of Tetrahydrofiuorenones from 5-Alkylidene Meldrum's Acids

摘要

The one-pot synthesis of tetrahydrofiuorenones,the core 6-5-6 tricyclic structural motif found in norditerpenoid natural products,from alkylidene Meldrum's acids via thermal Diels-Alder/BF3 centre dot OEt_2-catalyzed Friedel-Crafts acylation reactions is described.A series of tetrahydrofiuorenones was assembled in good yields,and the Diels-Alder/Friedel- Crafts acylation protocol allowed modification of the substitution within the rings.