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Showing papers on "Claisen rearrangement published in 1984"





Journal ArticleDOI
TL;DR: In this paper, α-Acylation of the ketene silyl acetal of methyl β,β,β-trifluoropropionate and α-allylation via the ester enolate Claisen rearrangement of the 2-alkenyl trifluorsopionates are described which provide the corresponding α-CF3 β-ketoesters and αCF3 γ,δ-unsaturated acids, respectively.

49 citations


Journal ArticleDOI
TL;DR: In this article, a 1-butyl-2-propenyl vinyl ether was treated with a hexane solution of Me3Al (1.0 M, 2.2 equiv) in CH2ClCH2Cl at 25 °C afforded 5-decen2-ol (91% yield, E⁄Z=47⁄53), which was produced by the [3,3] sigmatropic rearrangement and successive methylation.
Abstract: Organoaluminium compounds, R3Al, promote the Claisen rearrangement of allyl vinyl ether derivatives at room temperature under transfer of R or H as a nucleophile to the aldehydic carbon. Treatment of 1-butyl-2-propenyl vinyl ether with a hexane solution of Me3Al (1.0 M, 2.2 equiv) in CH2ClCH2Cl at 25 °C afforded 5-decen-2-ol (91% yield, E⁄Z=47⁄53), which was produced by the [3,3] sigmatropic rearrangement and successive methylation. The rearrangements with alkynylation, alkenylation, and hydrogenation are also achieved. The regular Claisen rearrangement products, or γ,δ-unsaturated aldehydes (ketones), are obtained at 25 °C in good to excellent yields with Et2AlSPh (2.5 equiv) or the combination of Et2AlCl (2.0 equiv) and PPh3 (2.2 equiv).

48 citations


Journal ArticleDOI
TL;DR: In this paper, the Ireland-Claisen rearrangement of allylic glycolate esters is described in which the stereocontrol of the prochiral sp 2 sites is achieved by the allylic oxygen substitutent.

47 citations



Journal ArticleDOI
TL;DR: Syntheses basees sur la spiro-annelation d'α-methylene cetone derivees du cycloheptane and du benzocyclohepticene, par condensation de Diels-Alder and transposition de Claisen as mentioned in this paper.
Abstract: Syntheses basees sur la spiro-annelation d'α-methylene cetone derivees du cycloheptane et du benzocycloheptene, par condensation de Diels-Alder et transposition de Claisen

44 citations


Journal ArticleDOI
TL;DR: Two novel and simple methods for preparing 4-aminomethyl-2, 3, 4, 9-tetrahydrothiopyrano [2,3-b] indoles are described, which led to fused tryptamine analogues which were found to have strong analgesic activity.
Abstract: Two novel and simple methods for preparing 4-aminomethyl-2, 3, 4, 9-tetrahydrothiopyrano [2, 3-b] indoles are described. Both involve thio-Claisen rearrangements of indol-2-yl propargyl sulfides as a key step which affords thiopyrano [2, 3-b] indoles in good yields. Elaboration of these compounds led to fused tryptamine analogues which were found to have strong analgesic activity. The mechanism of this novel rearrangement is discussed.

44 citations


Journal ArticleDOI
TL;DR: Synthese de R-2 chromenones-4 par transposition de Claisen cyclisation a partir de RCOO-2' acetophenones; synthetse de Naphto [1,2-b] pyrannones 4 a partire d'acetyl-2 RCOO -1 naphtalenes as discussed by the authors.
Abstract: Synthese de R-2 chromenones-4 par transposition de Claisen puis cyclisation a partir de RCOO-2' acetophenones; synthese de R-2 methyl-3 chromenones-4 a partir de RCOO-2' propiophenones; synthese de R-3 naphto [1,2-b] pyrannones-4 a partir d'acetyl-2 RCOO-1 naphtalenes

39 citations



Journal ArticleDOI
TL;DR: In this paper, the authors described the Claisen rearrangement of several ethyl allyloxyindole-2-carboxylates, including 7-allyl-6-hydroxyindoles, which are readily prepared by the thermolysis of azidocinnamates in toluene.
Abstract: The Claisen rearrangement of several ethyl allyloxyindole-2-carboxylates is described. These indoles are readily prepared by the thermolysis of azidocinnamates in toluene, which undergo concomitant ring closure and Claisen rearrangement when heated in bromobenzene. Rearrangement of the 6-allyloxy derivatives (10) and (17) proceeds regioselectively to give the corresponding 7-allyl-6-hydroxyindoles. The method has been used to prepare 7-(1,1-dimethylallyl)-, 7-(3-methylbut-2-enyl)-, and 7-linalyl-indoles in synthetically useful reactions.

Journal ArticleDOI
TL;DR: In this article, an enantiospecific synthesis of the title compound was described which involves the TiCl4-promoted cyclization of the chiral allylic silane having formyl group, which was obtained via the Claisen rearrangement of ( R, E )-1-trimethylsilyl-1buten-3-ol.

Journal ArticleDOI
TL;DR: Synthese stereoselective de dihydro-3,6 isopropyl-6 pyrannecarboxylates-2 de methyle a partir d'isopropcycl-5 vinyl-6 dioxanne-1,4ones-2
Abstract: Synthese stereoselective de dihydro-3,6 isopropyl-6 pyrannecarboxylates-2 de methyle a partir d'isopropyl-5 vinyl-6 dioxanne-1,4ones-2

Journal ArticleDOI
TL;DR: The optically active lactone 1a, prepared previously by the claisen rearrangement, serves as a starting material for the synthesis of (−) alcohol 7b which has been ultilized by Ireland in the synthesis OF tirandamycic acid 8a as mentioned in this paper.


Journal Article
TL;DR: In this article, a partir du dimethylamide de l'acide trimethyl-3,3,6 heptene-4oique, soit par addition of l'acetide methyl-3 butene-2oique avec le lithio-2 dithianne-1,3
Abstract: On prepare des amides de l'acide chrysanthemique par deux voies, soit a partir du dimethylamide de l'acide trimethyl-3,3,6 heptene-4oique, soit par addition de l'acide methyl-3 butene-2oique avec le lithio-2 dithianne-1,3

Journal ArticleDOI
TL;DR: In this article, a new route to 4-substituted indoles involves aza claisen rearrangement of a meta-subtituted N-allyl aniline followed by ozonolytic cleavage of the resultant 1,2,3-trisubstitized Nallyl derivative.


Journal ArticleDOI
TL;DR: Blastmycinone has been synthesized based on diastereoselective synthesis of (2R,3S)-2-hydroxy-3-(1-propenyl)heptanoic acid by the ester enolate Claisen rearrangement of (R)-(E)-1-methyl-2-heptenyl glycolate and stereoregressive reduction of α-hydrox ketone with Zn(BH4)2.


Journal ArticleDOI
TL;DR: In this article, the preparation and Claisen rearrangement of highly substituted allyl vinyl ethers is described, and it is demonstrated that the thermal and anionic versions of the CCA are capable of creating vicinal quaternary centers.

Journal ArticleDOI
TL;DR: The presence of an amino substituent at the 2-vinyl position in substituted allyl vinyl ethers facilitates low-temperature rearrangements through [3,3]- or [1, 3]-sigmatropic shifts, which lead to the aminoaldehydes (3) and (5), respectively as mentioned in this paper.
Abstract: The presence of an amino substituent at the 2-vinyl position in substituted allyl vinyl ethers facilitates low-temperature rearrangements through [3,3]- or [1,3]-sigmatropic shifts, which lead to the aminoaldehydes (3) and (5), respectively.


Journal ArticleDOI
TL;DR: In this article, organoaluminium reagents such as i Bu 3 A1, PhC=CA1Et 2, and Et 2 A1SPh mediate the title reactions in three different directions.


Journal ArticleDOI
TL;DR: In this article, a substituent controlled Claisen rearrangement is employed as the key reaction for a facile construction of chiral intermediates for the synthesis of pseudomonic acids from diacetyl-L-arabinal.

Journal ArticleDOI
TL;DR: In this article, a reductive Claisen rearrangement of allyloxyanthraquinones with sodium dithionite in dimethylformamide/water is described.
Abstract: Gentle heating of allyloxyanthraquinones with sodium dithionite in dimethylformamide/water effects a rapid and controlled rearrangement to give high yields of 2-allylhydroxyanthraquinones.Starting from quinizarin, key intermediates for two synthetic routes to 4-demethoxydaunomycinone have been prepared from products by means of two such reductive Claisen rearrangements.

Journal ArticleDOI
TL;DR: In this article, the Ireland variant of the Claisen rearrangement was used to transform unsaturated acid into unsaturated alcohol, which is then hydroborated to obtain homoallylic alcohols.