title: Enantioselective approach to quinolizidines: total synthesis of cermizine D and formal syntheses of senepodine G and cermizine C.
abstract: The formal syntheses of C5-epi-senepodine G and C5-epi-cermizine C have been accomplished through a novel diastereoselective, intramolecular amide Michael addition process. The total synthesis of cermizine D has been achieved through use of an organocatalyzed, heteroatom Michael addition to access a common intermediate. Additional key steps of this sequence include a matched, diastereoselective alkylation with an iodomethylphenyl sulfide and sulfone-aldehyde coupling/reductive desulfurization sequence to combine the major subunits. The utility of a Hartwig-style C-N coupling has been explored on functionally dense coupling partners. Diastereoselective conjugate additions to α,β-unsaturated sulfones have been investigated, which provided the key sulfone intermediate in just six steps from commercially available starting materials. The formal syntheses of senepodine G and cermizine C have been accomplished through an intramolecular cyclization process of a N-Boc-protected piperidine sulfone.
authors.affiliation: Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, USA.
authors.forename: Nagarathanam
authors.initials: N
authors.lastname: Veerasamy
authors.forename: Erik C
authors.initials: EC
authors.lastname: Carlson
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Collett
authors.forename: Mrinmoy
authors.initials: M
authors.lastname: Saha
authors.forename: Rich G
authors.initials: RG
authors.lastname: Carter
mesh_terms: D006574:Heterocyclic Compounds, 2-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D054837:Quinolizidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D006574:Heterocyclic Compounds, 2-Ring; D054837:Quinolizidines; C518697:cermizine C; C529947:cermizine D; C518698:senepodine G