Lewis Acid Promoted Addition Reactions of Organometallic Compounds

Abstract

The importance of the Lewis acidic nature of organometals in addition reactions to CX bonds (X = heteroatom) has been well documented.1 The complexation of organometallic compounds with CX bonds is considered to be the origin of the promotion of the addition reactions and the generation of chemo-, regio- or stereo-selectivities. The complexation phenomena are discussed in detail in Chapter 1.10, of this volume. In reactions of simple organometals such as alkyl-magnesiums or -aluminums, a single organometallic species undertakes both of the tasks involved in the CC bond formation process: complexation and nucleophilic attack. For example, reaction of benzophenone with Me3Al in a 1:1 ratio is reported to give a monomeric 1:1 complex at room temperature, which decomposes to dimethyl-aluminum 1,1-diphenylethoxide at 80 °C (equation 1).2