Linked Life Data

18549281

Source:http://linkedlifedata.com/resource/pubmed/id/18549281

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
2008-7-11
pubmed:abstractText
The effects of different amino acid catalysts on the stereoselectivity of the direct intermolecular aldol reactions between alpha-hydroxyketones and isobutyraldehyde or 4-nitrobenzaldehyde have been studied with the aid of density functional theory methods. The transition states of the crucial C-C bond-forming step with the enamine intermediate addition to the aldehyde for the proline and threonine-catalyzed asymmetric aldol reactions are reported. B3LYP/6-31+G** calculations provide a good explanation for the opposite syn vs anti diastereoselectivity of these two kinds of amino acid catalysts (anti-selectivity for the secondary cyclic amino acids proline, syn-selectivity for the acyclic primary amino acids like threonine). Calculated and observed diastereomeric ratio and enantiomeric excess values are in good agreement.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1520-6904
pubmed:author
pubmed:issnType
Electronic
pubmed:day
18
pubmed:volume
73
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5264-71
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Origins of opposite syn-anti diastereoselectivities in primary and secondary amino acid-catalyzed intermolecular aldol reactions involving unmodified alpha-hydroxyketones.
pubmed:affiliation
Institute for Computational Science and Engineering, Laboratory of New Fiber Materials and Modern Textile, Qingdao University, Qingdao, Shandong 266071, China. faplhl@eyou.com
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't