Showing papers on "Annulation published in 1984"
TL;DR: Par chauffage de derives de cyclobutenone, formation de vinyl-cetenes; ces derniers se combinent avec des alcyne-1yl-ethers, -sulfures et -amines selon un processus de cycloaddition [2+2] regioselective as mentioned in this paper.
Abstract: Par chauffage de derives de cyclobutenone, formation de vinyl-cetenes; ces derniers se combinent avec des alcyne-1yl-ethers, -sulfures et -amines selon un processus de cycloaddition [2+2] regioselective. Preparation de methylthio-3-, methoxy-3 et methylamino-3 phenols
152 citations
TL;DR: In this paper, strong base and chlorotrimethylsilane were used to convert α, β- β, γ-unsaturated esters to the corresponding mixed vinylketene acetals.
133 citations
118 citations
TL;DR: In this paper, the cyclisation par l'acetate de manganese III de cetoacides ou d'alcoxycarbonylacides en γ-lactones is described.
Abstract: Etude de la cyclisation par l'acetate de manganese III de cetoacides ou d'alcoxycarbonylacides en γ-lactones: par exemple cyclisation de l'acide cyclohexene-2 acetylacetique en perhydro cyclopenta [cd] benzofurannone-2; application au malonate de cyclohexene-2yle a l'acide methyl-7 oxo-3 octene-6oique, a l'acide β-oxo cyclohexene-3 propionique et a l'acide cyclopentene-2 acetylacetique (obtention de perhydro furo [4,3,2-cd] benzofurannedione, d'oxatricyclododecanedione, de perhydro cyclopenta [c] furannedione-1,6, de perhydro indeno [1,6-bc] furannedione-2,3 et de perhydro indeno [2,1-b:6,1-b'-c'] difurannedione
118 citations
TL;DR: The reaction de Diels-Alder des complexes α,β-acetyleniques de carbene-Cr, a lieu avec un certain nombre de dienes, peuvent servir de synthons pour les esters propiolates substitues as mentioned in this paper.
Abstract: La reaction de Diels-Alder des complexes α,β-acetyleniques de carbene-Cr, a lieu avec un certain nombre de dienes. Ces complexes alcynyl peuvent servir de synthons pour les esters propiolates substitues. Les cycloadditions et annelations peuvent etre realisees en tandem ou concurremment
70 citations
63 citations
62 citations
42 citations
TL;DR: In this paper, α-oxoketendithioacetals are shown to be useful intermediates for benzoannelation of α-methylene ketones by reactions with allylmagnesium bromide followed by cationic cyclizations of the resulting carbinolacetals.
36 citations
TL;DR: In this article, the reduction electrochimique sur electrode de mercure dans le DMF-tetrafluoroborate de tetraethylammonium, de the (bis-[benzyl tosyl amino]-2',5' ptolyl-2 methyl-2 cyclopentanedione-1,3.
Abstract: Etude de la reduction electrochimique sur electrode de mercure dans le DMF-tetrafluoroborate de tetraethylammonium, de la (bis-[benzyl tosyl amino]-2',5' p-tolyl-2 methyl-2 cyclopentanedione-1,3. Preparation de (benzyl-1 benzylamino-8 dimethyl-6,9 hexahydro-1,2,3,4,5,6) benzoazocine-1
34 citations
TL;DR: An easily effected aromatic annelation involving the reaction of arylimidoyl radicals with alkynes to give quinolines was described in this paper, where the reaction was shown to be reversible.
Abstract: An easily effected aromatic annelation is described, involving the reaction of arylimidoyl radicals with alkynes to give quinolines.
TL;DR: In this article, a newly developed annulation method involves reaction of cyclic β-trifluoromethanesulfonyloxy α,β-unsaturated esters (e.g. 14−16) with lithium (phenylthio)(trimethylstannyl)cuprate, alkylation of the resultant products, and transmetalation-cyclization of suitable substrates.
TL;DR: In this paper, a 12-step synthetic sequence was used to transform the readily available keto acetal into the sesquiterpenoid (±)-pentalenene, the key conversion of which involved a new, recently developed methylenecyclopentane annulation process.
Abstract: Transformation of the readily available keto acetal (10) into the novel sesquiterpenoid (±)-pentalenene (1) is accomplished via a 12-step synthetic sequence, the key conversion [(13) into (15)] of which involves a new, recently developed methylenecyclopentane annulation process.
TL;DR: In this paper, a short, efficient total synthesis of the racemic form of the marine sesquiterpenoid (-)-∆9(12)-capnellene (1) is described.
Abstract: A short, efficient total synthesis of the racemic form of the marine sesquiterpenoid (-)-∆9(12)-capnellene (1) is described. The key steps of the synthesis are two methylenecyclopentane annulation sequences (14 → 16; 22 → 24) involving the CuBr-Me2S→BF3 • Et2O catalyzed conjugate addition of the Grignard reagent 13 to the enones 14 and 22, followed by intramolecular alkylation (KH, tetrahydrofuran) of the resultant adducts 15 and 23, respectively
TL;DR: On prepare la dimethyl-7,7 hexahydro benzo [c] furannone-1 a partir de ladimethyl-2,2 cyclohexanone as discussed by the authors.
Abstract: On prepare la dimethyl-7,7 hexahydro benzo [c] furannone-1 a partir de la dimethyl-2,2 cyclohexanone. La methode est appliquee a la synthese de l'isodrimenine et du coloratadienolide
TL;DR: Les reactifs du titre sont prepared a partir du chloro-3 propene et du chlorure de benzenesulfenyle as mentioned in this paper, et.
Abstract: Les reactifs du titre sont prepares a partir du chloro-3 propene et du chlorure de benzenesulfenyle
TL;DR: In this article, the Diels-Alder reaction of 3,4-methylenedioxy - ω - nitrostyrene with butadiene and the Robinson annelation with phenylpyruvic acid with methyl vinyl ketone, respectively, was converted into (±)Δ2-α-lycoren-7-one (22b) by Torssell.
TL;DR: La cyclisation de cycloheptene-1'yl-4 butanone-3 en presence of MeAlCl 2 conduit a un melange 9/1 de perhydro methyl-8a azulenones-1 trans et cis as mentioned in this paper.
Abstract: La cyclisation de la cycloheptene-1'yl-4 butanone-3 en presence de MeAlCl 2 conduit a un melange 9/1 de perhydro methyl-8a azulenones-1 trans et cis
TL;DR: In this paper, four isomers of the sesquiterpene isocomene have been synthesized in high yields and in a stereocontrolled fashion from the tricyclic triquinane 1 obtained by the cyclopentene annulation method.
TL;DR: Direct couplings of α-bromomethylacrylates and doubly charged succinate ion are described in this article, where they are shown to work well together.
TL;DR: Several bicyclic α-chloro enones obtained through Greene annulation of cyclic olefins are shown to undergo efficient, two step, enone transposition via Luche reduction and aq. formic acid treatment as mentioned in this paper.
TL;DR: Asymmetric Robinson annelation of racemic diketones leads to enantiodifferentiation which depends on the presence or the absence of an angular methyl group as mentioned in this paper, which is not the case here.
Abstract: Asymmetric Robinson annelation of racemic diketones leads to enantiodifferentiation which depends on the presence or the absence of an angular methyl group.
TL;DR: On prepare l'epiaflavine par annelations multiples a partir du citronellol et de la methyl-4cyclohexene-2one as mentioned in this paper.
Abstract: On prepare l'epiaflavine par annelations multiples a partir du citronellol et de la methyl-4cyclohexene-2one
TL;DR: In this paper, a total synthesis of Δ9(12)-capnellene, a cis-anti-cis-tricyclo[6.3.0]undecane sesquiterpene of marine origin, is described.
Abstract: A total synthesis of Δ9(12)-capnellene, a cis-anti-cis-tricyclo[6.3.0.02,6]undecane sesquiterpene of marine origin, is described. Starting with bicyclic enone 5, which was prepared by a Nazarov cyclization, the remaining portion of the molecule is elaborated by means of a new and relatively efficient cyclopentenone annulation scheme. The relative stereochemistries of the chiral centers are properly incorporated by taking advantage of prevailing steric factors.
TL;DR: In this article, a one-step synthesis of 4-ketohydroazuleneiron complexes from troponeiron tricarbonyl was described, where the tricarboxylic acid was used as the base.
TL;DR: In this article, treatment of 1,2-bis(4′, 4′-dimethyl-2′-oxazolin-2´-yl)ethane with butyllithium produced the corresponding dianion, which on exposure with 1, ω -dihalides gives cyclic derivatives.
TL;DR: In this article, new synthetic methods for the preparation of 1,4-diketones, 4-oxopentanals, and 5-oxohexanals were developed based on the oxidation of terminal olefins to methyl ketones with PdCl2-CuCl-O2 as a key reaction.
Abstract: New synthetic methods for the preparation of 1,4-diketones, 4-oxopentanals, and 5-oxohexanals were developed based on the oxidation of terminal olefins to methyl ketones with PdCl2-CuCl-O2 as a key reaction. They constitute useful annulation methods.