79341-39-2Relevant academic research and scientific papers
Degenerate Carbon Skeleton Isomerization of the Cyclopentyl Cation in the Gas Phase. Experimental and Theoretical Evidence for the Existence of a Pyramidal C5H9(+) Cation as an Intermediate in the Unimolecular Ethylene Elimination
Franke, Wilfried,Schwarz, Helmut,Thies, Helga,Chandrasekhar, Jayaraman,Raque' Schleyer, Paul von,et al.
, p. 2808 - 2824 (2007/10/02)
The investigation of 13C2-labelled isotopomeric bromocyclopentanes (5a, b), cyclobutylmethyl bromide (6a) and 5-bromo-1-pentenes (7a, b) clearly demonstrates, that unimolecular ethylene loss from the gaseous + ions generated from both the cyclic and acyclic precursors is preceded by complete carbon scrambling.Whereas the degenerate isomerization 8a 8b can, in principle, proceed either via the bisected cyclobutylmethyl cation 9 or via the non-classical, pyramidal cation 3, the MINDO/3 calculations reveal, that ethylene loss from C5H9+ involves 3 as an intermediate.From 3 a transition state is reached which can be regarded as a partially opened cyclopropyl cation "solvated" by interaction with C2H4.Descriptions of the syntheses of the 13C2-labelled bromides are given.
