Mimicking Non‐Canonical Radical Cyclizations in the Synthesis of Dibenzocyclooctadiene Natural Products

Unique chemical structures of biologically active natural products are often created by oxidative cyclizations catalysed by non-canonical iron oxygenases (involving long-lived radicals). Herein, our group‘s efforts to mimic these biosynthetic transformations for the synthesis of highly oxidized dibenzocyclooctadiene lignan natural products using redox neutral photocatalysis with Okada's redox active ester are summarized.

Abstract

Unique chemical structures that are often characteristic of biologically active natural products are often created by oxidative cyclizations. Many of these reactions are catalysed by ‘non-canonical’ or ‘thwarted’ iron oxygenases that appear to involve long-lived radicals. This perspective summarizes our group‘s efforts to mimic these biosynthetic transformations for the synthesis of highly oxidized dibenzocyclooctadiene lignan natural products using redox neutral photocatalysis. We describe the evolution of this research program, which hinges on the use of Okada's redox active ester, and show how multiple factors control the fate of the resulting radicals.