Synthesis of a tricyclic lactone embodying the ABC-ring system of stephaoxocanidine, by tin(IV) chloride-assisted sulfonamido acetal cyclization and an aromatization promoted by triethylamine.Bianchi

BIANCHI, DARIO A.; KAUFMAN, TEODORO S.

Arkivoc

Arkat USA Inc.

Año: 2003 p. 178 - 188

1424-6376

The synthesis of the polysubstituted 8-oxa-1-azaphenalene lactone which embodies the ABC-ring system of stephaoxocanidine, a tetracyclic isoquinoline alkaloid recently isolated from the tubers of Stephania cepharantha Hayata, is reported. Elaboration of was carried out by means of the camphorsulfonic acid-assisted lactonization of coupled to a titanium(IV) chloride-mediated acetal cyclization of the resulting lactone to form the tricyclic intermediate followed by the base-promoted aromatization of the latter to constitutes an advanced key intermediate for the total synthesis of stephaoxocanidine, the simplest stephaoxocane. which embodies the ABC-ring system of stephaoxocanidine, a tetracyclic isoquinoline alkaloid recently isolated from the tubers of Stephania cepharantha Hayata, is reported. Elaboration of was carried out by means of the camphorsulfonic acid-assisted lactonization of coupled to a titanium(IV) chloride-mediated acetal cyclization of the resulting lactone to form the tricyclic intermediate followed by the base-promoted aromatization of the latter to and final benzylic bromination. Lactone constitutes an advanced key intermediate for the total synthesis of stephaoxocanidine, the simplest stephaoxocane.