Controlled Dealkylation of Alkyl Esters with Halide Salts and Application in Tandem Catalyzed Protodecarboxylation of Organic Formates

The selective activation of unactivated alkyl esters for C(sp³)–C bond formation remains a major challenge in cross-coupling chemistry. Here, we report a systematic study on the dealkylation of alkyl formates using iodide salts, revealing the pivotal role of the Lewis acidic countercation (K⁺, Na⁺, Li⁺, Ca²⁺, Mg²⁺, Al³⁺) in accelerating C–O bond cleavage. Kinetic analyses demonstrate a seven-order-of-magnitude rate enhancement when replacing LiI with AlI₃. To highlight the synthetic potential of this finding, we further integrate this reactivity into a tandem catalytic system combining AlI₃ and a ruthenium catalyst, achieving efficient protodecarboxylation of alkyl formates to alkanes with up to 82 % yield.