Expanding the Chemistry of Acyl Diazo Electrophile as a Tunable Warhead for Covalent Targeting of KRAS (G12D) Mutant

Covalent warheads are indispensable in the design and development of targeted covalent inhibitors (TCIs). Here, we designed and evaluated acyl diazo probes as an aspartic acid/glutamic acid targeted warhead. Among these probes, P1 demonstrated chemoselectivity for carboxyl residues, even under complex physiological conditions, effectively modifying the proteome in both cell lysates and live cells. Subsequently, we incorporated the warhead onto MRTX-1133, a potent ligand of the KRAS (G12D) mutant, to generate a novel TCI called KN2-H. Compared with other mutants, KN2-H demonstrated covalent modification specifically targeting the KRAS (G12D) mutant, with notable chemoselectivity. It also possessed strong antiproliferative activity against KRAS (G12D) mutant cell lines by downregulating RAS oncogenic signaling. Our findings provide a novel strategy for designing novel TCIs targeting carboxyl residues, based on acyl diazo warheads.