http://www.mdpi.com/journal/molecules/special_issues/polyketide/ Related Special Issues in other Journals Polyketide in Pharmaceuticals {snippet name="submission_info"} http://www.mdpi.com/1420-3049/16/7/6092/ Polyketides are a diverse class of medically important natural products whose biosynthesis is catalysed by polyketide synthases (PKSs), in a fashion highly analogous to fatty acid biosynthesis. In modular PKSs, the polyketide chain is assembled by the successive condensation of activated carboxylic acid-derived units, where chain extension occurs with the intermediates remaining covalently bound to the enzyme, with the growing polyketide tethered to an acyl carrier domain (ACP). Carboxylated acyl-CoA precursors serve as activated donors that are selected by the acyltransferase domain (AT) providing extender units that are added to the growing chain by condensation catalysed by the ketosynthase domain (KS). The action of ketoreductase (KR), dehydratase (DH), and enoylreductase (ER) activities can result in unreduced, partially reduced, or fully reduced centres within the polyketide chain depending on which of these enzymes are present and active. The PKS-catalysed assembly process generates stereochemical diversity, because carbon–carbon double bonds may have either cis- or trans- geometry, and because of the chirality of centres bearing hydroxyl groups (where they are retained) and branching methyl groups (the latter arising from use of propionate extender units). This review shall cover the studies that have determined the stereochemistry in many of the reactions involved in polyketide biosynthesis by modular PKSs. http://www.mdpi.com/1420-3049/16/7/6092/ Wed, 20 Jul 2011 00:00:00 CEST Molecules 2011-07-20 16 7 Review 6092 6115 1420-3049 The Stereochemistry of Complex Polyketide Biosynthesis by Modular Polyketide Synthases 2011-07-20 doi: 10.3390/molecules16076092 David H. Kwan Frank Schulz http://www.mdpi.com/1420-3049/16/6/4850/ Studies on the synthesis of macrosphelide B via an intramolecular nitrile oxide-olefin cycloaddition (INOC) is described. In particular, an asymmetric INOC approach using phase transfer catalysts seems to be a potentially efficient and versatile procedure for the construction of the macrolactone skeleton of macrosphelide B in terms of facial selectivity. Our preliminary and unprecedented stereoselective procedure is anticipated to be usefully applied through further studies for the synthesis of the macrosphelide family. http://www.mdpi.com/1420-3049/16/6/4850/ Fri, 10 Jun 2011 00:00:00 CEST Molecules 2011-06-10 16 6 Article 4850 4860 1420-3049 Synthetic Studies on Bioactive Natural Polyketides: Intramolecular Nitrile Oxide-Olefin Cycloaddition Approach for Construction of a Macrolactone Skeleton of Macrosphelide B 2011-06-10 doi: 10.3390/molecules16064850 Seung-Mann Paek Young-Ger Suh