Linked Life Data

18798628

Source:http://linkedlifedata.com/resource/pubmed/id/18798628

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
41
pubmed:dateCreated
2008-10-8
pubmed:abstractText
Computational studies at the BLYP/6-31G(d) level (supplemented by BCCD(T)/cc-pVDZ calculations) suggest that in aryl-substituted 1,2-diethynylbenzenes, steric effects disfavor the thermal C1-C6 diradical cyclization reaction (Bergman) and electronic effects favor the regiovariant C1-C5 cyclization to the extent that the C1-C5 process should become an important reaction pathway in the thermolyses of such compounds. Experimentally, thermolyses of 1,2-bis(2,4,6-trichlorophenylethynyl)benzene, a particularly favorable case, yields only products derived from C1-C5 cyclization [specifically, 1-(2,4,6-trichlorobenzylidene)-2-(2,4,6-trichlorophenyl)-1H-indene and its hydrogenation product 3-(2,4,6-trichlorobenzyl)-2-(2,4,6-trichlorophenyl)-1H-indene], and even for the parent hydrocarbon 1,2-bis(phenylethynyl)benzene, the formation of C1-C5 cyclization products is competitive with the major Bergman reaction. Although some C1-C5 cyclization products are probably formed by transfer hydrogenation from 1,4-cyclohexadiene (commonly included in such reactions), thermolyses in the absence of 1,4-CHD as well as deuterium labeling studies confirm the existence of direct C1-C5 diradical cyclizations for diaryl-substituted enediynes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1520-5126
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13549-51
pubmed:dateRevised
2009-1-22
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Thermal C1-C5 diradical cyclization of enediynes.
pubmed:affiliation
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't