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Metal‐Free Intermolecular Azide–Alkyne Cycloaddition Promoted by Glycerol
Author(s) -
RodríguezRodríguez Marta,
Gras Emmanuel,
Pericàs Miquel A.,
Gómez Montserrat
Publication year - 2015
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.201503858
Subject(s) - cycloaddition , chemistry , alkyne , adduct , intermolecular force , reactivity (psychology) , photochemistry , azide , metal , copper , glycerol , alcohol , polymer chemistry , catalysis , organic chemistry , molecule , medicine , alternative medicine , pathology
Abstract Metal‐free intermolecular Huisgen cycloadditions using nonactivated internal alkynes have been successfully performed in neat glycerol, both under thermal and microwave dielectric heating. In sharp contrast, no reaction occurs in other protic solvents, such as water, ethanol, or diols. DFT calculations have shown that the BnN 3 /glycerol adduct promotes a more important stabilization of the corresponding LUMO than that produced in the analogous BnN 3 /alcohol adducts, favoring the reactivity with the alkyne in the first case. The presence of copper salts in the medium did not change the reaction pathway (Cu(I) acts as spectator), except for disubstituted silylalkynes, for which desilylation takes place in contrast to the metal‐free system.