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Nitrenium ion-mediated alkene bis-cyclofunctionalization: total synthesis of (-)-swainsonine.

ABSTRACT: The total synthesis of (-)-swainsonine from 2,3-O-isopropylidene-D-erythrose in 12 steps and an overall yield of 28% is reported. The pivotal transformation in our route to this indolizidine alkaloid is the formation of the pyrrolidine ring and C-8a/8 stereodiad through the diastereoselective, bis-cyclofunctionalization of an ?,?-unsaturated O-alkyl hydroxamate. This transformation is believed to proceed via the intramolecular capture of an N-acyl-N-alkoxyaziridinium ion generated by the diastereoselective addition of a singlet acylnitrenium ion to the pendant alkene.

SUBMITTER: Wardrop DJ

PROVIDER: S-EPMC3100185 | biostudies-other | 2011 May

REPOSITORIES: biostudies-other

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Nitrenium ion-mediated alkene bis-cyclofunctionalization: total synthesis of (-)-swainsonine.

Wardrop Duncan J DJ Bowen Edward G EG

Organic letters 20110412 9

The total synthesis of (-)-swainsonine from 2,3-O-isopropylidene-D-erythrose in 12 steps and an overall yield of 28% is reported. The pivotal transformation in our route to this indolizidine alkaloid is the formation of the pyrrolidine ring and C-8a/8 stereodiad through the diastereoselective, bis-cyclofunctionalization of an γ,δ-unsaturated O-alkyl hydroxamate. This transformation is believed to proceed via the intramolecular capture of an N-acyl-N-alkoxyaziridinium ion generated by the diaster ...[more]

PMID: 21486077

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