Linked Life Data

11383599

Source:http://linkedlifedata.com/resource/pubmed/id/11383599

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2001-5-31
pubmed:abstractText
Two types of general and practical enantioselective catalysts, namely, bimetallic complexes and Lewis acid-Lewis base bifunctional catalysts were developed based on the concept of multifunctional catalysis. In the first part of this review, the first example of a catalytic enatioselective nitro-Mannich reaction as well as a direct catalytic enantioselective aldol reaction of 2-hydroxyacetophenone using bimetallic complexes is discussed. The new complex, composed of ytterbium, potassium, and BINOL in a ratio of 1:1:3, promoted the nitro-Mannich reaction of nitromethane with up to 91% ee. On the other hand, second generation ALB catalyzed an enantioselective and diastereoselective nitro-Mannich reaction of nitroalkanes in up to 83% ee with a diastereomeric ratio up to 7:1. Moreover, the reaction of aldehydes with 2-hydroxyacetophenone in the presence of LLB, KHMDS, and H2O selectively gave the corresponding anti-alpha,beta-dihydroxy ketones in up to 95% ee and, in the presence of the catalyst prepared from linked-BINOL and 2 eq of Et2Zn, selectively afforded the syn-alpha,beta-dihydroxy ketones in up to 86% ee. In the second part, the development of new catalysts displaying a Lewis acidity and a Lewis basicity is described. The Lewis acid of the catalyst activates aldehydes, imines, acyl quinoliniums, and ketones. At the same time, the Lewis base activates the nucleophile (TMSCN). Catalysts of this type produced a highly enantioselective cyanation of these electrophiles. Application of the catalytic enantioselective cyanosilylation of aldehydes to a total synthesis of epothilones is also described.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0009-2363
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
511-24
pubmed:dateRevised
2005-11-16
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Multifunctional asymmetric catalysis.
pubmed:affiliation
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Japan. mshibasa@mol.f.u-tokyo.ac.jp
pubmed:publicationType
Journal Article, Review