Hybrid Electrochemically-paired Light Irradiated Organic Synthesis (Acronym: HELIOS)

The synergy of visible light and electrical energy has been employed for decades in water splitting to hydrogen, but only recently was used to power the synthesis of higher value complex organic molecules (natural products, pharmaceuticals). Synthetic photoelectrochemistry (PEC) is receiving notable attention due to its enhanced scope of redox transformations, sustainability, and selectivity compared to photo- or electrochemistry alone.

Synthetic electrochemistry (EC) is a useful synthetic tool that replaces atom uneconomical chemical redox agents with simple electrons and protons. However, in most EC reactions and in all PEC reactions, only one half-reaction of the cell is optimized to generate value; the other half-reaction sacrifices its own electrode or redox additives. 'Paired' electrolysis, where both half-reactions afford useful species, is key to sustainability and efficiency.

HELIOS will discover, develop and disseminate paired synthetic PEC reactions. Intermediates generated by both half-reactions are converged in novel, creative chemical transformations, including:

i) marriage of radicals or ions generated by each half-reaction to furnish phenethylamines and azetidines, valued pharmaceuticals

ii) ring-fusing reactions that furnish bicyclic scaffolds, toward molecules with high 3D character urgently required in drug discovery iii) alcohol inversion reactions that are catalytic, environmentally-friendly and use mild conditions

'Multifunctional' catalysts will be used that can be electro-activated in both cathodic and anodic half-cells, to photochemically generate and stabilize reactive intermediates.

HELIOS i) harnesses electrical and light energy to rapidly convert cheap, abundant chemical feedstocks to value-added complex molecules and ii) improves the sustainability and selectivity of synthetic PEC and EC processes. HELIOS opens an entirely new dimension of chemical reactivity that will revolutionize the way chemists use redox to synthesize molecules.