A molecular electron density theory study of the participation of tetrazines in aza-Diels-Alder reactions.
RSC Adv
; 10(26): 15394-15405, 2020 Apr 16.
Article
in En
| MEDLINE
| ID: mdl-35495430
ABSTRACT
The reactions of eight tetrazines of increased electrophilic character with nucleophilic tetramethyl ethylene (TME) and with electrophilic tetracyanoethylene (TCE) have been studied using Molecular Electron Density Theory. These reactions are domino processes comprising an aza-Diels-Alder (ADA) reaction followed by an extrusion of molecular nitrogen, yielding a dihydropyridazine. Analysis of the conceptual DFT (CDFT) indices showed an increase of the electrophilicity and a decrease of the nucleophilicity of tetrazines with an increase of the electron-withdrawing character of the substituent. A very good correlation between the global electron density transfer at the transition structures and the activation enthalpies for the ADA reactions involving TME was found. However, tetrazines have no tendency to react with electrophilic ethylenes such as TCE. Bonding Evolution Theory (BET) analysis of the ADA reaction of dinitro tetrazine with TME showed that the activation energy is mainly associated with the continuous depopulation of the C-C and C-N double bonds.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
RSC Adv
Year:
2020
Document type:
Article
Country of publication:
ENGLAND
/
ESCOCIA
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GB
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GREAT BRITAIN
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INGLATERRA
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REINO UNIDO
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SCOTLAND
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UK
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UNITED KINGDOM