Linked Life Data

18052247

Source:http://linkedlifedata.com/resource/pubmed/id/18052247

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
51
pubmed:dateCreated
2007-12-20
pubmed:abstractText
The mechanism of the enantioselective cyanosilylation of ketones catalyzed by tertiary amino-thiourea derivatives was investigated using a combination of experimental and theoretical methods. The kinetic analysis is consistent with a cooperative mechanism in which both the thiourea and the tertiary amine of the catalyst are involved productively in the rate-limiting cyanide addition step. Density functional theory calculations were used to distinguish between mechanisms involving thiourea activation of ketone or of cyanide in the enantioselectivity-determining step. The strong correlation obtained between experimental and calculated ee's for a range of substrates and catalysts provides support for the most favorable calculated transition structures involving amine-bound HCN adding to thiourea-bound ketone. The calculations suggest that enantioselectivity arises from direct interactions between the ketone substrate and the amino-acid derived portion of the catalyst. On the basis of this insight, more enantioselective catalysts with broader substrate scope were prepared and evaluated experimentally.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1520-5126
pubmed:author
pubmed:issnType
Electronic
pubmed:day
26
pubmed:volume
129
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15872-83
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Cooperative catalysis by tertiary amino-thioureas: mechanism and basis for enantioselectivity of ketone cyanosilylation.
pubmed:affiliation
Department of Chemistry & Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural