Beilstein J. Org. Chem.2023,19, 1923–1932, doi:10.3762/bjoc.19.143
alternative synthetic methodologies for functionalized 1,2-diazepines has drawn extensive attention [14][15][16][17][18][19][20][21]. One of the most attractive strategies to synthesize the 1,2-diazepine motif represents the [4 + 3] cycloaddition reaction between activated azoalkenes and 1,3-dipolarophiles
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Graphical Abstract
Scheme 1:
Representative [4 + 3] cycloaddition reactions of MBH carbonates derived from isatins.
Beilstein J. Org. Chem.2016,12, 2471–2477, doi:10.3762/bjoc.12.241
alkylations of amines and ammonia with azoalkenes (generated from α-halohydrazones) were demonstrated as an efficient approach to poly(hydrazonomethyl)amines – a novel class of polynitrogen ligands. An intramolecular cyclotrimerization of C=N bonds in tris(hydrazonomethyl)amine to the respective 1,4,6,10
-tetraazaadamantane derivative was demonstrated.
Keywords: azoalkenes; α-halogen hydrazones; heterocage compounds; hydrazone ligands; Michael addition; Introduction
Hydrazones are extensively used as key structural units in the design of various functional molecular and supramolecular architectures [1][2][3][4][5
straightforward methodology based on multiple Michael-type additions of azoalkenes A (generated from α-halogen azacarbonyl precursor 1 [35][36][37][38][39]) to amines or ammonia (Scheme 1).
Though the chemistry and synthetic potential azoalkenes A have been a subject of considerable interest in the recent years