A piece of the C 6 H 9 + potential energy surface: Rearrangement of spiropentylmethyl cation and an elegant nonclassical spiro[2.3]hex‐5‐yl cation
Author(s) -
Shobe David S.
Publication year - 2020
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.4064
Subject(s) - chemistry , bicyclic molecule , solvolysis , potential energy surface , crystallography , computational chemistry , stationary point , potential energy , transition state , stereochemistry , molecule , atomic physics , physics , organic chemistry , mathematical analysis , mathematics , hydrolysis , catalysis
Abstract Stationary points in a region of the C 6 H 9 + potential energy surface was explored using the CBS‐QB3 method. The region includes the spiropentylmethyl cation and all three bicyclohexyl bridgehead cations. The relative energies of these bicyclohexyl cations are −54 kJ/mol for bicyclo[2.2.0]hex‐1‐yl cation and −75 kJ/mol for bicyclo[2.1.1]hex‐1‐yl cation, with spiropentylmethyl cation being 0 kJ/mol. Bicyclo[2.1.1]hex‐1‐yl cation is a transition state, while bicyclo[3.1.0]hex‐1‐yl cation is not a stationary point after all, but rearranges without barrier to 2‐methylenecyclopentyl cation. Although spiropentylmethyl cation and spiro[2.3]hex‐4‐yl cation are local minima on the CBS‐QB3 potential energy surface, their existence is questioned. Spiro[2.3]hex‐5‐yl cation has an unusual structure, with the central carbon having five nearest neighbors with interatomic distances between 1.5 and 1.7 Å. The results for rearrangement of the spiropentylmethyl cation are in general agreement with previous solvolysis studies.