Linked Life Data

17338576

Source:http://linkedlifedata.com/resource/pubmed/id/17338576

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2007-3-23
pubmed:abstractText
The sulfoxide-induced preference for a migrating trajectory in the vinylallene [1,5]-H sigmatropic shift (resulting in stereodefined trienes in the conceptual equivalent of torquoselectivity in electrocyclizations), originally reported by Okamura, has been computationally studied at the B3LYP/6-311++G(3df,2p)//B3LYP/6-31++G(d,p) level. The face selectivity this group induces in the [1,5]-H shift is enhanced by bulky geminal substituents and is not reproduced by any of the other (more than 20) substituents tested. Analysis of transition-state geometries or charges and evaluation of steric effects did not show any correlation with the preferences. The origin of this selectivity is thought to lie in a secondary orbital interaction (SOI) involving the termini of the pericyclic array and the sulfinyl group which is only observed for this substituent. This secondary orbital interaction, arising from the favorable energies of the orbitals involved, is enhanced in the transition structure due to a better orbital overlap (piC2-C3-->sigma*C1-S), which correlates with a piC2-C3-->sigma*C6-H SOI, which is more important in the transition structure, that weakens the C-H bond, thus lowering the energy of the corresponding transition structure.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Mar
pubmed:issn
0022-3263
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
72
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2617-24
pubmed:year
2007
pubmed:articleTitle
Sulfoxide-induced stereoselection in [1,5]-sigmatropic hydrogen shifts of vinylallenes. A computational study.
pubmed:affiliation
Departamento de Química Orgánica, Universidade de Vigo, Lagoas, Marcosende, 36310 Vigo, Spain.
pubmed:publicationType
Journal Article