Chemistry - A European Journal
10.1002/chem.201901667
FULL PAPER
Conclusions
the existence of transition state TS (presents an imaginary frequency) or
equilibrium structure. The solvent effect was considered in all the
calculations using PCM (polarizable continuum model) and the solvent
considered was toluene.21 Charges from electrostatic potential using a grid
based method (ChelpG) were computed, as well the electrostatic potential
surfaces (ESP).22 Natural Bond Orbital (NBO) analysis were performed in
In summary, we report for the first time a successful
intramolecular hydroamination reaction of chalcogenoalkynes to
2-substituted chalcogenylindoles in the absence of any catalyst or
basic conditions. A broad range of derivatives were obtained in
moderate to high yields. This report presents a methodology with
inverse regioselectivity for chalcogen functionalisation of indoles.
In addition, we could also synthesise the unpublished tellurium
indole derivative. The change from selenium to tellurium and
sulfur analogues leads us to conclude that the selenium moiety
assists the reaction, making the use of catalyst unnecessary.
order to elucidate the factors responsible for stabilization of this
molecule.23All the calculations were performed using Gaussian 16
package. The electrostatic surface potentials were rendering using
GaussView 5.0 program.25
24
Acknowledgements
Experimental Section
We are grateful to CAPES, CNPq, INCT-CMN and FAPERGS
for financial and technical support.
1
General: For general experimental details, characterisation data, and H
and 13C NMR spectra for novel compounds, see the Supporting
Information.
Keywords: Selenium • Indoles • Chalcogenoalkynes • Thermal
Cyclisation • DFT study
General protocol for preparation of chalcogenalkyne (1a-1m)
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a
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The reaction coordinate for the formation of molecule 5a from molecule 4a
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[
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