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The Photochemical Reaction of Vinylaziridines and Vinylazetidines with Chromium(0) and Molybdenum(0) (Fischer) Carbene Complexes
Author(s) -
Rivero Alexandra R.,
Fernández Israel,
Sierra Miguel A.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302029
Subject(s) - ketene , carbene , cycloaddition , chemistry , chromium , molybdenum , nucleophile , aziridine , photochemistry , medicinal chemistry , ring (chemistry) , organic chemistry , catalysis
The [5+2] and [6+2] cycloaddition reactions of vinylaziridines and vinylazetidines with ketenes generated photochemically from chromium(0) and molybdenum(0) Fischer carbene complexes have been investigated. These processes constitute a straightforward and efficient route to azepanones and azocinones, respectively. The peculiar electronic properties of the metalated ketenes allow for the introduction of electron‐rich substituents in the final cycloadducts, a difficult task using conventional organic chemistry procedures. The versatility of the process is demonstrated by using Cr 0 Fischer bis(carbene) complexes as metalated bis(ketene) precursors. These species produce tethered bis(azepanone)s in a single step under mild reaction conditions. Density functional theory calculations point to a stepwise reaction pathway through the initial nucleophilic attack of the nitrogen atom of the aziridine on the metalated ketene, followed by ring closure of the zwitterionic intermediate formed.