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This article provides a detailed report of our efforts to synthesize the dithiodiketopiperazine (DTP) natural products (−)‐epicoccin G and (−)‐rostratin A using a double C(sp3)−H activation strategy. The strategy's viability was first established on a model system lacking the C8/C8' alcohols. Then, an efficient stereoselective route including an organocatalytic epoxidation was secured to access a key bis‐triflate substrate. This bis‐triflate served as the functional handles for the key transformation of the synthesis: a double C(sp3)−H activation. The successful double activation opened access to a common intermediate for both natural products in high overall yield and on a multigram scale. After several unsuccessful attempts, this intermediate was efficiently converted to (−)‐epicoccin G and to the more challenging (−)‐rostratin A via suitable oxidation/reduction and protecting group sequences, and via a final sulfuration that occurred in good yield and high diastereoselectivity. These efforts culminated in the synthesis of (−)‐epicoccin G and (−)‐rostratin A in high overall yields (19.6 % over 14 steps and 12.7 % over 17 steps, respectively), with the latter being obtained on a 500 mg scale. Toxicity assessments of these natural products and several analogues (including the newly synthesized epicoccin K) in the leukemia cell line K562 confirmed the importance of the disulfide bridge for activity and identified dianhydrorostratin A as a 20x more potent analogue. [ABSTRACT FROM AUTHOR]

Our ongoing effort towards the development of highly selective transition-metal-catalysed C-H activation processes has led to the expansion of the Catellani reaction. In a Pd0/PdII/PdIV-catalysed domino reaction, an aryl iodide, alkyl iodide and tert-butyl acrylate were combined to synthesize the carbon framework of the novel lignan (+)-linoxepin. The enantioselective synthesis highlights the work accomplished in our group and provides an excellent procedure for the reliable and scalable synthesis of architecturally complex scaffolds. This report outlines the synthetic approaches towards this interesting class of biologically active molecules. After the key Catellani/Heck reaction, our synthesis features a Leimeux-Johnson oxidation and a titanium tetrachloride mediated aldol condensation. Finally, a tuneable Mizoroki-Heck reaction was performed to furnish not only the natural product (+)-linoxepin but also its isoform, which we have named isolinoxepin. [ABSTRACT FROM AUTHOR]

A correction to the article "Application of the Palladium-Catalysed Norbornene-Assisted Catellani Reaction Towards the Total Synthesis of (+)-Linoxepin and Isolinoxepin" that was published in the November 6, 2014 issue.