A stable E1cb intermediate, β-cyanoethyl anion (1 β), has been synthesized in the gas phase at room temperature under thermal conditions via the fluoride-induced desilylation of 3-(trimethylsilyl) propionitrile. The reactivity and thermodynamic properties of this ion are reported. The cyano group is found to lower the proton affinity of 1 β by 29±6 kcal/mol, which represents a particularly large substituent effect. High-level ab initio and density functional ...
