Electrolyzers that reduce carbon dioxide (CO2) into chemicals and fuels often use high-purity gaseous CO2 feedstocks that need to be isolated from upstream carbon capture units. If CO2 were to be captured directly from air, the eluent is likely to be an aqueous solution rich in bicarbonate ions (HCO3-). This scenario provides the impetus to electrolytically reduce these bicarbonate-rich carbon capture solutions into the same products as a CO2 electrolyzer. We report here an electrolyzer configuration that couples the conversion of bicarbonate to CO at the cathode with hydrogen oxidation at an anode. This unique system is capable of reaching a commercially-relevant current density of 500 mA cm-2 at merely 2.2 V, which is >0.5 V more efficient than any other reported electrolyzer that reduces HCO3- or CO2 at these current densities.

<p>The spiroindimicins are a unique class of chlorinated indole alkaloids characterized by three heteroaromatic rings structured around a congested spirocyclic stereocenter. Here, we report the first total synthesis of (+)-spiroindimicin A, which bears a challenging C-3’/C-5’’-linked spiroindolenine. We detail our initial efforts to effect a biomimetic oxidative spirocyclization from its proposed natural precursor, lynamicin D, and describe how these studies shaped our final abiotic 9-step solution to this complex alkaloid built around a key asymmetric Pd-catalyzed spirocyclization. Scalable access to spiroindimicins A, H, and their congeners has enabled discovery of their activity against several parasites relevant to human health, providing potential starting points for new therapeutics for the neglected tropical diseases leishmaniasis and African sleeping sickness.</p>