The total synthesis of (+)-demethoxycardinalin 3 is described. The synthetic strategy features the synthesis of dimeric Fischer carbene and its use in a bidirectional Dötzbenzannulationreaction to set the dimeric structure of the cardinalins. The oxa-Pictet−Spengler reaction was used to construct the pyran rings. The synthesis is completed in seven steps and an overall yield of 7%.
With bioactivity-guided phenotype screenings, a potent anti-inflammatory compound f152A1 has been isolated, characterized and identified as the known natural product LL-Z1640-2. Metabolic instability precluded its use for the study on animal disease models. Via total synthesis, a potent, metabolicallystabilized analog ER-803064 has been created; addition of the (S)-Me group at C4 onto f152A1 has resulted