Reaction of alkyl and aryl grignard reagents with trifluoroacetyldihydropyrans and other cyclic ?-alkoxy-?, ?-unsaturated trifluoromethylketones
Reaction of alkyl and aryl grignard reagents with trifluoroacetyldihydropyrans and other cyclic ?-alkoxy-?, ?-unsaturated trifluoromethylketones
Alkyl and aryl Grignard reagents react with cyclic ?-alkoxy-?, ?-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.
additions, a-strain, grignard reagents, hydride transfer, tetrahydropyrans, trifluoromethylketoneshuman-leukocyte elastase, benzyl copper reagents, ?-hydroxy ketones, tishchenko reactions, nonpeptidic inhibitors, antennal esterases, carbonyl-compounds, mediated addition, in-vitro, reduction
10039-10055
Mellor, J. M.
d9b993ad-31be-4f91-8ea3-1723cd1c23bc
Reid, G.
ff85ed93-1d4e-4c2b-a9b7-d927a61c4abe
El-Sagheer, A. H.
c37c0aa8-20a2-4fd9-b2cf-3a891182db00
El-Tamany, E. S. H.
e500b10f-b3bd-4548-b0dd-bf05b4e83076
15 December 2000
Mellor, J. M.
d9b993ad-31be-4f91-8ea3-1723cd1c23bc
Reid, G.
ff85ed93-1d4e-4c2b-a9b7-d927a61c4abe
El-Sagheer, A. H.
c37c0aa8-20a2-4fd9-b2cf-3a891182db00
El-Tamany, E. S. H.
e500b10f-b3bd-4548-b0dd-bf05b4e83076
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 ?-alkoxy-?, ?-unsaturated trifluoromethylketones.
Tetrahedron, 56 (51), .
(doi:10.1016/S0040-4020(00)00975-3).
Abstract
Alkyl and aryl Grignard reagents react with cyclic ?-alkoxy-?, ?-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.
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Published date: 15 December 2000
Keywords:
additions, a-strain, grignard reagents, hydride transfer, tetrahydropyrans, trifluoromethylketoneshuman-leukocyte elastase, benzyl copper reagents, ?-hydroxy ketones, tishchenko reactions, nonpeptidic inhibitors, antennal esterases, carbonyl-compounds, mediated addition, in-vitro, reduction
Identifiers
Local EPrints ID: 18929
URI: http://eprints.soton.ac.uk/id/eprint/18929
ISSN: 0040-4020
PURE UUID: 8d368514-bb2c-4746-9adc-9a8b58ed4873
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Date deposited: 16 Dec 2005
Last modified: 15 Mar 2024 06:09
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Author:
J. M. Mellor
Author:
G. Reid
Author:
A. H. El-Sagheer
Author:
E. S. H. El-Tamany
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