0000000000524469
AUTHOR
Ekhlass Nassar
Experimental and theoretical study of the [3+2] cycloaddition of carbonyl ylides with alkynes
[EN] The [3 + 2] cycloaddition reaction between carbonyl ylides generated from epoxides and alkynes (phenylacetylene, methyl propiolate, methyl but-2-ynoate and methyl 3-phenylpropiolate) to give substituted 2,5-dihydrofurans was investigated. The effect of indium(III) chloride on the outcome of the reaction was studied in the case of phenylacetylene and methyl propiolate. The thermal reaction between the carbonyl ylide coming from 2,2-dicyano-3-phenyloxirane and both methyl propiolate and methyl but-2-ynoate was theoretically investigated using DFT methods in order to explain the reactivity and regioselectivity observed.
A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes.
International audience; Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower acti…