Reaction of alkyl and aryl grignard reagents with trifluoroacetyldihydropyrans and other cyclic β-alkoxy-α, β-unsaturated trifluoromethylketones
Mellor, J. M., Reid, G., El-Sagheer, A. H. and El-Tamany, E. S. H. (2000) Reaction of alkyl and aryl grignard reagents with trifluoroacetyldihydropyrans and other cyclic β-alkoxy-α, β-unsaturated trifluoromethylketones. Tetrahedron, 56, (51), 10039-10055. (doi:10.1016/S0040-4020(00)00975-3).
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Alkyl and aryl Grignard reagents react with cyclic β-alkoxy-α, β-unsaturated trifluoromethylketones by 1,il-addition to give as the major products, for example, cis-2,3-disubstituted tetrahydropyrans. In most examples ring opening leads to stereoselective formation of rearranged hemiketals as minor products. Under other conditions with 2,2,2-trifIuoro-1-(2-ethoxy-3,4-dihydro-2H-5-pyranyl)-1-ethanone stereoselective ring opening leads to acyclic aldehydes, as minor products and, by the major pathway, to a series of diols by addition of further equivalents of the Grignard reagent. Tn the absence of further Grignard reagent at higher temperatures internal hydride transfer can afford acyclic esters.
|Keywords:||additions, a-strain, grignard reagents, hydride transfer, tetrahydropyrans, trifluoromethylketoneshuman-leukocyte elastase, benzyl copper reagents, β-hydroxy ketones, tishchenko reactions, nonpeptidic inhibitors, antennal esterases, carbonyl-compounds, mediated addition, in-vitro, reduction|
Q Science > QD Chemistry
|Divisions:||University Structure - Pre August 2011 > School of Chemistry
|Date Deposited:||16 Dec 2005|
|Last Modified:||02 Mar 2012 12:26|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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