1,2-Diaza-1,3-butadienes: just a nice class of compounds, or powerful tools in organic chemistry? Reviewing an experience

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Divergent Construction of Pyrazoles via Michael Addition of N‑Arylhydrazones to 1,2-Diaza-1,3-dienes

partially_open4noThe base (NaH)-promoted Michael addition of N-arylhydrazones (AHs) with 1,2-diaza-1,3-dienes (DDs) produces unprecedented β-azohydrazone adducts. Strategically, the use of AHs as acyl anion equivalents (d1 synthon) and DDs as α-electrophiles (a2 synthon) of carbonyl compounds open the way to two important classes of pyrazole compounds.embargoed_20160409Serena mantenuto; Fabio Mantellini; Orazio Attanasi; Gianfranco FaviMantenuto, Serena; Mantellini, Fabio; Attanasi, ORAZIO ANTONIO; Favi, Gianfranc

α-Azido Ketones, Part 8: Base-Induced Coupling of α-Azido Ketones with a 1,2-Diaza-1,3-diene as a Michael Acceptor1

Carbanions generated from various acyclic and cyclic α-azido ketones in the presence of bases were reacted with ethyl 3-[(carbamoylimino)amino]but-2-enoate as a Michael acceptor to give the corresponding adducts. The adducts of acyclic azides were unstable and eliminated hydrazoic acid to give the corresponding ethyl 2-[1-[(carbamoylamino)imino]ethyl]-4-oxo-4-phenylbut-2- enoates as (E,E/Z,E)-diastereomeric mixtures. The relative configuration of these diastereomers was determined by X-ray analysis. Adducts of cyclic α-azido ketones were obtained in diastereomerically pure form, with the exception of 2-azidobenzosuberone