title: The cobalt way to angucyclinones: asymmetric total synthesis of the antibiotics (+)-rubiginone B2, (-)-tetrangomycin, and (-)-8-O-methyltetrangomycin.
abstract: A cobalt(I)-mediated convergent and asymmetric total synthesis of angucyclinones with an aromatic B ring has been developed. In the course of our research, we synthesized three naturally occurring anguclinone derivatives, namely, (+)-rubiginone B(2) (1), (-)-8-O-methyltetrangomycin (2), and (-)-tetrangomycin (3). By combining 3-hydroxybenzoic acid, 3-methoxybenzoic acid, citronellal, and geraniol as starting materials in a convergent way, we were able to synthesize chiral triyne chains, which were cyclized with [CpCo(C(2)H(4))(2)] (Cp=cyclopentadienyl) by means of an intramolecular [2+2+2] cycloaddition to their corresponding tetrahydrobenzo[a]anthracenes. Successive oxidation and deprotection steps led to the above-mentioned natural products 1-3.
authors.affiliation: Fachbereich Chemie and Konstanz Research School Chemical Biology, Universität Konstanz, Universitätsstrasse 10, Postfach 720, 78457 Konstanz, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kesenheimer
authors.forename: Aris
authors.initials: A
authors.lastname: Kalogerakis
authors.forename: Anja
authors.initials: A
authors.lastname: Meissner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Groth
mesh_terms: D000880:Anthraquinones / Q000138:chemical synthesis* / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry; D001551:Benz(a)Anthracenes / Q000138:chemical synthesis / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D015394:Molecular Structure; D000095602:Angucyclines and Angucyclinones
chemical_list: D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D001551:Benz(a)Anthracenes; D003035:Cobalt; C510997:angucyclinone; C510996:rubiginone B2; D000095602:Angucyclines and Angucyclinones; C059960:MM 47755; C103671:tetrangomycin