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In the late 1990s, the Caribbean octocoral Pseudopterogorgia elisabethae became the target of extensive chemical investigations leading to the isolation and characterization of a remarkable number of diterpenoid secondary metabolites. Most of these newly discovered compounds are based on so far unprecedented carbon skeletons and often feature unusual structural characteristics. Besides their exciting...
The synthesis of complex natural products still remains as the bottleneck for the biological evaluation of such compounds. In contrast to the biosyntheses, vinylogous aldol reactions can incorporate more than one acetate or propionate building block into the growing polyketide chain. To facilitate such reactions either enolate activation or aldehyde activation is required. For both variations, selective...
Methanophenazine is a naturally occurring phenazine of nonbacterial origin, which has recently been isolated from the cytoplasmic membrane of Methanosarcina mazei Gö1 archaea. It is not only the first and so far the sole phenazine derivative from archaea, but also the first one that is acting as an electron carrier in a respiratory chain – a biologic function equivalent to that of ubiquinones in mitochondria...
A brief overview of the occurrence and biological activity of carbazole alkaloids is provided. Recent progress in the development of novel methodologies for the synthesis of substituted biologically active carbazole alkaloids is summarized. The described methods are based on the transition metal-mediated oxidative coupling of arylamines with unsaturated six-membered hydrocarbons, thus leading to highly...
Aza-Claisen rearrangements (3-aza-Cope rearrangements) have gained an increasing interest in synthetic organic chemistry. Originally, the exceptionally high reaction temperatures of this hetero variant of the well-known 3,3-sigmatropic reaction limited their applicability to selected molecules. Since about 1970, charge acceleration enabled a significant reduction of the reaction temperature to be...
The pamamycins are structurally intriguing 16-membered macrodiolides displaying a wide range of interesting biological activities. A comprehensive survey of the total syntheses reported in this area so far and the various synthetic approaches to the hydroxy acid constituents of the pamamycins described to date is presented.
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