Sulfonic acid anchored on silica, SiO₂@SO₃H: A superior solid acid catalyst for quick and solvent‐free reductive‐deoxygenation of ketones with NaBH₃CN

Abstract

NaBH3CN as a modified hydroborate agent and due to a strong withdrawing CN group does not show any reducing ability to reduce functional groups in the absence of acidic media (pH ~ 3–4). In this study, the immobilized sulfonic acid on silica, SiO2@SO3H, was prepared and applied as a new solid acid catalyst for extremely enhancing the reducing ability of NaBH3CN. The influence of SiO2@SO3H was highlighted by performing the quick and green reduction of structurally diverse carbonyl compounds involving aldehydes, ketones, α,β‐unsaturated enals and enones, α‐diketones, and acyloins to the corresponding alcohols or alkanes with NaBH3CN. By the NaBH3CN/SiO2@SO3H system, aldehydes were reduced to the corresponding alcohols and ketonic compounds to alkanes as reductive‐deoxygenation products. All reduction reactions were carried out within 3 min at room temperature and under solvent‐free conditions to afford the products in high to excellent yields (90–98%).