Iron Carbonyl Assisted Synthesis of 1,2-Diazepin-3-ones from Cyclic Diazenes and Alkynes

Abstract

<jats:p>Bicyclic 1,2-diazepin-3-ones 1a-c, 2a, c are prepared by an iron carbonyl mediated reaction sequence from alkynes and cyclic 1,2-diazenes. The latter are first converted into hexacarbonyl diiron complexes which react with two molecules of an alkyne to afford tricyclic carbonyl iron compounds I -III. Oxidative degradation with bromine leads to these novel heterocycles whose structure is confirmed by an X-ray analysis of 1b.</jats:p>