New Stereoselective Route to the Epoxyquinol Core of Manumycin-Type Natural Products. Synthesis of Enantiopure (+)-Bromoxone, (-)-LL-C10037α, and (+)-KT 8110
A practical route is decribed for the preparation of the C7N core of manumycin-type compounds. Starting from p-benzoquinone, optically pure compounds in both forms can be prepared via enzymatic resolution of a derived diacetoxy conduritol. A diepoxy aminoinositol is accessible which can function for formation of enantiopure epoxyquinones and quinols. Examples are given for acylation reactions of this amine with several acyl derivatives. With this approach (-)-LL-C10037α and quinones such as (+)-KT-8110 with 5A,6S-configuration can be synthesized through oxidation. In addition a short route to (+)-bromoxone is described. Most steps include simple epoxide formation and cleavage reactions which all can be carried out in a high stereoselective manner.
Block, Oliver,Klein, Georg,Altenbach, Hans-Josef,Brauer, David J.
p. 716 - 721
(2007/10/03)
The synthesis of alisamycin, nisamycin, LL-C10037α and novel epoxyquinol and epoxyquinone analogues of manumycin A
Versatile synthetic routes are described for the preparation of a range of epoxyquinol and epoxyquinone analogues of the antitumour antibiotic manumycin A lacking the lower side chain, and these procedures have also been applied to prepare the bioactive natural product LL-C10037α. The extension of this methodology to provide a general synthetic route to the manumycin family of antibiotics is discussed and exemplified by the first total synthesis of alisamycin and ent-alisamycin. This route includes the novel, stereoselective organometallic addition of the Corey-Wollenberg reagent (E- 2-tributylstannylethenyllithium) to the manumycin nucleus and palladium catalysed Stille coupling technology for the introduction of the polyunsaturated 2-amino-3-hydroxycyclopentenone derived amide. Similar methodology has also been employed to complete the first total synthesis of the antibiotic nisamycin.
Taylor, Richard J. K.,Alcaraz, Lilian,Kapfer-Eyer, Isabelle,Macdonald, Gregor,Wei, Xudong,Lewis, Norman
p. 775 - 790
(2007/10/03)
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