Electrophilic Diazoalkane Substitution

In general, the hydrogen atom of diazomethyl compounds can be substituted by electrophilic reagents. In addition to halogenation, metallation, and nitration reactions, alkylation reactions are also very important. Insertion reactions with neutral electrophiles such as carbonyl compounds, azomethines, or donor-substituted olefins complement the direct substitution reactions with S_N1 activated halides and donor-stabilised or aromatic cations. The scope of the long known acylation reaction is broadened by application of isocyanates and isothiocyanates as electrophiles. The process termed electrophilic diazoalkane substitution ideally supplements the classical diazoalkane syntheses. 1. Introduction 2. Metallation Reactions 2.1. The Metal Amide Method 2.2. Transmetallation 2.3. Special Methods 3. Halogenation Reactions 4. Nitration Reactions 5. Alkylation Reactions 5.1. Substitution Reactions 5.2. Insertion Reactions 6. Acylation Reactions 6.1. Carboxylic Acid Chlorides 6.2. Carboxylic Acid Anhydrides 6.3. Acyl Isocyanates and Acyl Isothiocyanates 7. Prospects