Electrophilic and Nucleophilic Substitution at the C a -Atom of Diazo Compounds

1 Electrophilic and Nucleophilic Substitutions at the C(a)-Atom of Diazo Compounds 

There are various reasons that may lie behind this development. First, for almost 100 years, electrophilic substitutions were a domain of aromatic chemistry and, at least before Huisgen s review (1955) on the reactivity of diazoalkanes, the large majority of organic chemists did not spend much time on the question that, apparently, there are no similarities between aromatic and aliphatic diazo compounds. Second, it is obvious — even today — that electrophilic substitution reactions of aliphatic diazo compounds are more complex and, therefore, less predictable than the substitution of sp -hybridized C-atoms in aromatic and aliphatic compounds by arenediazonium ions. 

Schollkopf et al. (1969) tried, therefore, to improve the yield of the diazonitro compound 9.2 by adding good proton acceptors like pyridine or triethylamine, but they 

Diazo Chemistry II Aliphatic, Inorganic and Organometallic Conqfounds. By Heinrich Zollinger Copyright 1995 VCH Verlagsgesellschaft mbH ISBN 3-527-29222-5 

Diazodinitromethane can be obtained by further treatment of diazonitromethane with N2O5 (Schollkopf and Markusch, 1969, 1971). Schollkopf s method was applied by Regitz et al. (1979 c) to the nitration of a-diazomethylphosphoryl compounds. 

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