Aris Kalogerakis

The cobalt way to angucyclinones: asymmetric total synthesis of the antibiotics (+)-rubiginone B2, (-)-tetrangomycin, and (-)-8-O-methyltetrangomycin.

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.

Transition Metal Catalyzed Reactions in Organic Synthesis. Part 4. Total Synthesis of the Angucylinone Antibiotic (+)-Rubiginone B2.

SYNLETT 2003, No. 12, pp 1886–188829.09.2003 Advanced online publication: 19.09.2003 DOI: 10.1055/s-2003-41473; Art ID: G15103ST