Lewis Acidic Functions of Alkali Metal in Organometallic Reagents as Nucleophile

Lewis Acidic Functions of Alkali Metal in Organometallic Reagents as Nucleophile 

Highly nucleophilic organoalkali metal reagents are widely utilized in organic synthesis [7, 8]. The reaction with an electrophile provides a new bond that is a fundamental bond forming reaction. In this type of reaction, function of alkali metal as Lewis acid affects the reactivity and reaction selectivity. Recent extensive studies on mechanism have revealed that the mixed aggregation of substrate, alkali metal reagent, solvent, and additives control the reaction. 

This unique stereoselectivity change has been realized by mechanistic studies. The kinetic studies using IR spectroscopy has revealed that the reaction in toluene takes parallel dissociative and nondissociative pathways of TMEDA =fe [TMEDA] - - + fe [TMEDA] ). The reaction with low concentration of TMEDA (dissociative pathway) indicated inverse-first-order dependencies on n-BuLi concentration. Considering the solution structure of n-BuLi (12), the result 

3 Lewis Acid Property of Alkali Metals in Organoalkali Metal Reagents 1129 

With low concentration of TMEDA in toluene [(n-BuLi)2(TMEDA)(14)t 

---