BETA-CYANOETHYL ANION - LUSUS NATURAE

A stable E1(cb) intermediate, beta-cyanoethyl anion (1 beta), has been synthesized in the gas phase at room temperature under thermal condit ions via the fluoride-induced desilylation of 3-(trimethylsilyl)propio nitrile. The reactivity and thermodynamic properties of this ion are r eported. The cyano group is found to lower the proton affinity of 1 be ta by 29 +/- 6 kcal/mol, which represents a particularly large substit uent effect. High-level ab initio and density functional calculations have been carried out on 1 beta and several related species. The compu tational results are compared to each other, and their accuracy is eva luated.