Total synthesis of (±)-Taiwaniaquinol B via a domino intramolecular Friedel-Crafts acylation/carbonyl α-tert-alkylation reaction

Article abstract of DOI:10.1021/ja054447p

The first synthesis of taiwaniaquinol B, a 6-nor-5(6→7)abeoabietane-type diterpenoid exhibiting the uncommon fused 6-5-6 tricyclic carbon skeleton, was accomplished in 15 steps. A Lewis acid-promoted tandem intramolecular Friedel-Crafts/carbonyl α-tert-alkylation reaction was exploited as the core strategy for the synthesis of the sterically congested 1-indanone-containing tricyclic structure. This multiple carbon-carbon bond forming reaction exploits the unique reactivity of Meldrum's acid. The facile precursor synthesis makes this a useful methodology for the expedient modification and assembly of sterically congested 1-indanone-containing ring systems. Copyright