Linked Life Data

16709051

Source:http://linkedlifedata.com/resource/pubmed/id/16709051

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2006-5-19
pubmed:abstractText
We have carefully examined the organocopper-mediated reduction-alkylation of gamma-acetoxy or gamma,gamma-difluoro-alpha,beta-unsaturated-delta-lactams for the synthesis of (Z)-alkene- or (E)-fluoroalkene-containing diketopiperazine mimetics. Reduction of acetates 2, 12, 14, and difluorolactam 18 with higher-order cuprate reagents (Me3CuLi2 x LiI x 3 LiBr), followed by trapping the resulting metal dienolate with an electrophile in a one-pot procedure gave alpha-alkylated-beta,gamma-unsaturated-delta-lactams in good yields. Because of side-chain steric repulsion, we found that alkylation using relatively large electrophiles such as BnBr gave mostly 3,6-trans isomers by kinetic trapping of metal enolates. On the other hand, MeI-mediated alkylations predominantly provided the unexpected 3,6-cis isomers despite the presence of a bulky benzyl side chain. Based on density functional theory calculations, we concluded that formation of the 3,6-cis isomers was due to the occurrence of oxa-pi-allyllithium complexes 29 and 31.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-3263
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
71
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4118-29
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Synthesis of (Z)-alkene and (E)-fluoroalkene-containing diketopiperazine mimetics utilizing organocopper-mediated reduction-alkylation and diastereoselectivity examination using DFT calculations.
pubmed:affiliation
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't