Staudinger and aza-Wittig reactions

Diazepines represent an important class of bicyclic seven-membered heterocycles. They are the basis of several tranquilizers and are accessible from a-amino acid esters and o-azidobenzoyl chloride in the presence of triethylamine. The A/ -(o-azidobenzoyl)amino esters (333) formed in this way (Scheme 121) are cyclized by Staudinger and aza-Wittig reactions to give 2-ethoxy-l,4-benzodiazepin-5-ones (334) (92MI2). 

Keywords 1,2-Diaza-l,3-dienes, trimethylsililazide, copper(II) acetate, triphenyl phosphine, isocyanates/isothiocyanates, dichloromethane, room temperature, sequential foiu-component aza-Michael, Staudinger and aza-Wittig reactions, one-pot synthesis, 1,2-diaminoimidazoles... 

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