%0 Electronic Article
%A Kilaj, Ardita
%A Wang, Jia
%A Straňák, Patrik
%A Schwilk, Max
%A Rivero, Uxía
%A Xu, Lei
%A von Lilienfeld, O. Anatole
%A Küpper, Jochen
%A Willitsch, Stefan
%T Conformer-specific polar cycloaddition of dibromobutadiene with trapped propene ions
%N arXiv:2107.13858
%M PUBDB-2024-01849
%M arXiv:2107.13858
%D 2021
%X Diels-Alder cycloadditions are efficient routes for the synthesis of cyclic organic compounds. There has been a long-standing discussion whether these reactions proceed via stepwise or concerted mechanisms. Here, we adopt a new experimental approach to explore the mechanistic details of the model polar cycloaddition of 2,3-dibromo-1,3-butadiene with propene ions by probing its conformational specificities in the entrance channel under single-collision conditions in the gas phase. Combining a conformationally controlled molecular beam with trapped ions, we find that both conformers of the diene, gauche and s-trans, are reactive with capture-limited reaction rates. Aided by quantum-chemical and quantum-capture calculations, this finding is rationalised by a simultaneous competition of concerted and stepwise reaction pathways, revealing an interesting mechanistic borderline case.
%F PUB:(DE-HGF)25
%9 Preprint
%R 10.3204/PUBDB-2024-01849
%U https://bib-pubdb1.desy.de/record/607360