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The Elusive 1,4‐Diazabutatrienes: Lurking in the Shadows
Author(s) -
MarinLuna Marta,
Alajarin Mateo
Publication year - 2020
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202000518
Subject(s) - chemistry , synthon , isocyanide , electrophile , nucleophile , reactivity (psychology) , stereochemistry , combinatorial chemistry , divalent , moiety , organic chemistry , catalysis , medicine , alternative medicine , pathology
Isocyanides are isomers of cyanides in which the terminal carbon atom can exist in a divalent state. Their ambivalent electronic nature as nucleophile or electrophile and wide reactivity make the isocyanide scaffold a valuable synthon for the synthesis of structurally complex molecules, in particular azacycles. Although they are known to polymerize easily, the dimerization of isocyanides affording head‐to‐head dimers, namely 1,4‐diazabutatrienes R 1 ‐N=C=C=N–R 1 , has been scarcely explored. Nowadays the experimental isolation of this kind of heterocumulenes is still a challenge. In this minireview, covering a period of sixty years, we highlight the role of 1,4‐diazabutatienes as putative reaction intermediates in the homo‐ and heterodimerization of different types of isocyanides. Furthermore, we revise a set of reported reactions in which the formation of a transient 1,4‐diazabutatriene intermediate has not been proposed but could be considered as a plausible alternative.