The Chemistry of Phaeobacter gallaeciensis: A Nature-Inspired Approach to the Partial Synthesis of Roseobacticides

Abstract

Phaeobacter gallaeciensis and Emiliania huxleyi engage in a dynamic symbiosis that has a significant role in regulating the Earth's biogeochemical cycles. P. gallaeciensis promotes the growth of algae by producing growth promoters and antibiotics. However,algal senescence signals secreted by E. huxleyi cause this symbiosis to change from mutualistic to parasitic. In response to these signals, it is hypothesized that P. gallaeciensis undergoes a metabolic shift and converts these growth promoters into roseobacticides, which have potent anti-algal properties. A nature-inspired partial synthesis of roseobacticide-like structures has been explored in an effort to elucidate the mechanism of roseobacticide formation. It was found that derivatives of the growth promoters can be readily joined together via a dianionic alkylation to form a precursor to a roseobacticide-like structure. These results support the hypothesis that cycloheptene-1,3-dione and phenylacetyl-CoA are on the biosynthetic pathway to roseobacticide synthesis.