Synthesis of (±)-septicine

Article abstract of DOI:10.1016/S0040-4020(01)80639-6

The total synthesis of the indolizidine alkaloid, (±)-septicine (5) (27% overall yield) in 8 steps from dimethyl squarate is presented. The key step of the synthesis involves the ring expansion of 2,3-bis-(3,4-dimethoxyphenyl)-4-(1-pyrrolo)cyclobutenone 12 to the corresponding indolizine-5,8-dione 6. The synthesis is highly convergent and thus could be used for the synthesis of a variety of analogs.