Enhanced α-CH Acidity and Reactivity of Lewis Acid–Base Complexes in the Gas Phase


  • This work was supported by the National Science Foundation


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Borane complexation at the heteroatom increases the gas-phase C[BOND]H acidities of dimethyl sulfide, trimethylamine, and trimethylphosphane by up to 20 kcal mol−1. Deprotonation of the volatile Lewis acid–base complexes in the gas phase produces dipole-stabilized carbanions (see below) that do not rearrange to the more stable borate isomers. The complexation also enhances the reactivity of pendant methyl and ethyl groups toward substitution and elimination reactions.