Iminophosphorane, synthesis hydrolysis

A general synthesis of the secondary amines RNHMe and RNHEt has been developed starting from the iminophosphoranes (181). Alkylation with methyl or ethyl iodides (all other halides gave olefins) gave the salts (182) from which secondary amines were obtained on alkaline hydrolysis. 

Reduction of azides is a classical approach to primary amine synthesis. Treatment of 17 with sodium azide in DMF or in THF/H2O mixtures in the presence of phase transfer catalysts effects a quantitative conversion to the corresponding polymeric azide, 27. Recently the reduction of azides to primary amines via hydrolysis of iminophosphoranes produced by interaction of the azide with triethyl phosphite was reported.30 Application of this technique to the azidomethyl polymer, 27, as shown below, failed to produce a soluble polyamine. 

The smooth hydrolysis of imidoyl chlorides provides access to carbonam-ides from iminophosphoranes via an aza-Wittig reaction, without the occurrence of free acid or amino functions. This is of special advantage in the synthesis (Scheme 32) of sensitive substrates such as )8-lactam antibiotics (60) (77H719, 79JOC4393). 

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