Mechanistic Features of the Reactions of Organomagnesium Compounds

1. Introduction. 2. Properties of Grignard reagents. 2.1. Thermochemistry of alkylmagnesium reagents.2.1.1. Heat of formation of Grignard reagents.2.1.2. C-Mg bond dissociation energies.2.1.3. The oxygen-magnesium bond.2.2. Oxidation potentials of Grignard reagents. 2.3. Association equilibria in Grignard reagents.2.3.1. The Schlenk equilibrium.2.3.2. Selfassociation in Grignard reagents.2.3.3. Association between RMgX and carbonyl compounds.3. Reactions of benzophenone(s) with Grignard reagents.3.1. Prediction of a radical mechanism and early evidence. 3.2. Reactivity series and linear free energy correlations.3.3. Radical probes.3.4. A thermochemical approach.3.5. Kinetic isotope effects.3.5.1. Isotopic carbon and hydrogen in benzophenone.3.5.2. Deuterium substitution in the Grignard reagent.3.5.2.1. Primary isotope effect on the reduction process. 3.5.2.2. Secondary isotope effects on the addition process.3.6. CIDNP observations.3.7 A new school in the study of the reaction of benzophenone with Grignard reagents.4. Polar concerted reaction mechanisms.4.1. Addition to aliphatic ketones.4.2. Addition to acid derivatives4.3. Concerted transfer of b-hydrogen. Reduction. 5. Reactions with a,b-unsaturated carbonyl compounds. 6. ET substrates other than benzophenone.6.1. Metal catalysis. 6.1.1. The Kharasch reaction6.1.2. Reductive dimerisation of carbonyl compounds.6.2. Reactions with oxygen and with peroxides.6.3. Reactions with azobenzene.6.4. Reactions with cinnamic esters. 7. Solvent effects. 8. Conclusion. 9. References.