Oxidant-free cross-dehydrogenative oxyalkylation enables late-stage functionalization of drugs

Public summary

*Metal- and oxidant-free oxidative cross-dehydrogenative coupling enabled by γ radiation in aqueous solution.

*Aqueous γ-ray irradiation facilitates the generation of α-oxyalkyl radicals.

*Late-stage functionalization of FDA-approved drugs with high functional group tolerance (e.g., −NH₂ and −COOH).

*Enhanced pharmacokinetics of functionalized FAPI molecules demonstrated.

Abstract

Late-stage functionalization is an attractive strategy that allows chemists to bypass lengthy synthetic processes, facilitating the rapid generation of drug analogs with potentially enhanced pharmacokinetic and pharmacological properties. This study describes a novel approach for cross-dehydrogenative oxyalkylation, leveraging a unique γ-ray-enabled photoredox process to generate oxyalkyl radicals, followed by a Minisci-type addition in an aqueous solution. The metal- and oxidant-free aqueous conditions, coupled with excellent functional group compatibility, establish this method as a versatile protocol for the late-stage oxyalkylation of unprotected, structurally complex drug molecules. Notably, this method demonstrated improved pharmacokinetics in hydroxymethylated fibroblast activation protein inhibitor (FAPI) molecules, highlighting its potential to accelerate drug discovery efforts.