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Equilibrium and Reactivity of Grignard Reagents and Related Organometallic Compounds

This chapter explores the equilibrium of Grignard reagents, focusing on the stability of sp² carbanions, Metal-halogen exchange reactions, and their applications in various organic transformations. It discusses the reduction of sulfides through dimethylaminonaphthalene (LDMAN) and highlights the Shapiro reaction involving vinyllithium compounds. Further, the scope of reactions with alkylating agents, radical involvement, hydrogen abstraction, and ring closure using Allyllithium and benzyllithium reagents are analyzed. The chapter concludes with insights into competitive reactions like Meerwein-Pondorff-Verley reduction and processes involving Lewis acid-directed ortho-lithiation.

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Equilibrium and Reactivity of Grignard Reagents and Related Organometallic Compounds

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  1. Chapter 4

  2. Equilibrium of the compositions of Grignard reagents

  3. n-butyllithium and potassium t-butoxide(super base) Retention of configuration greater stability of sp2 carbanions

  4. Metal-halogen exchange

  5. Metal-halogen exchange

  6. Reduction of sulfides dimethylaminonaphthalene(LDMAN)

  7. Shapiro reaction vinyllithium compounds Nicolaou et al. J.Am.Chem.Soc.Vol.117,No.2,1995,634.

  8. Reactions with Alkylating Agents Limited in scope Radicals involved Hydrogen abstraction

  9. Allyllithium and benzyllithium reagents

  10. Ring closure Grignard reagents Reaction with Carbonyl Compoundds addition of Grignard reagents

  11. good leaving group +

  12. Competing reactions Meerwein- Pondorff-Verley reduction Enolization of the ketone

  13. homoallylic system 3 1 2 3 4 2 1 3 4 2 1 4

  14. Lewis acid

  15. directed ortho lithiation

  16. stable at low temperature

  17. (DMF)

  18. fast electron transfer step no free radicals are generated

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