Diazodicarboxylate ester

Heating aziridines and diazodicarboxylic esters with Ph3P in toluene gives... 

The enantioselectivity of a closely related reaction, the proline-catalyzed a-ami-nation of aldehydes with diazodicarboxylic esters, independently disclosed by List and by Jprgensen in 2002 [30], can also be accounted for by a List-Houk transition state model (Figure 2.10). 

The Mitsunobu reaction is used to convert an alcohol and an acid into an ester by formation of an activated alcohol (PhsP, diethyl diazodicarboxyl-ate), which then undergoes displacement with inversion by the carboxylate. Although this reaction works very well, it suffers from the fact that large quantities of by-products are produced, which generally require removal by chromatography. 

Interest in the Staudinger reaction of phosphines with azides, and the Mit-sunobu reaction involving nucleophilic attack by phosphorus at nitrogen in esters of diazodicarboxylic acids, has continued. Systems of the type (205) have been obtained from the reactions of secondary arylphosphines with azides. Treatment of these with butyllithium results in deprotonation to form the diaminophosphonium diazaylides (206). Phosphazenes have been prepared from azido-quinolines and -triazines, and also from diazoketones " and polycyanocyclopropanes. The Staudinger reaction has been employed in the synthesis of phosphorus-containing dendrimers, and in new approaches to amide and peptide synthesis. The reaction has also been used in a high-... 

The overall acceptance of hydrogen by a reducing reagent is demonstrated by item 10 of Table 8.5. Here, the diethyl ester of diazodicarboxylic acid (diethyl azodi-carboxylate [DEAD]) serves to oxidize 1-phenylpropanol to phenylpropanone while it is reduced to diethyl hydrazo-dicarboxylate in the process. Although the details are sketchy, a possible pathway is shown in Scheme 8.7. 

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