Thermodynamic and kinetic control of a chemical process is the key to access desired products and states. Changes are made when desired product is not accessible; one may manipulate the reaction with additional reagents, catalysts and/or protecting groups. Here we report the use of carbon dioxide to direct reaction pathways in order to selectively afford desired products in high reaction rates while avoiding the formation of byproducts. The utility of CO₂-mediated selective cyanohydrin synthesis was further showcased by broadening Kiliani-Fischer synthesis to offer an easy access to variety of polyols, cyanohydrins, linear alkylnitriles, by simply starting from alkyl- and arylaldehydes, KCN and atmospheric pressure of CO₂.