Showing papers on "Enone published in 1992"
TL;DR: In this article, the direct preparation of α-iodoenones by treatment of enones with I 2 /pyridine in CCl 4 was described, and the enones were then treated with enones in order to obtain α-idoenones.
208 citations
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TL;DR: The (S)-tryptophan derived catalyst has been used to effect enantioselective Mukaiyama-aldol and aldol-dihydropyrone annulation reactions of trimethylsilyloxy olefins and dienes.
183 citations
156 citations
TL;DR: An asymmetric aza-Diels-Alder reaction of an imines mediated by an in situ generated chiral boron complex is described and affords products of up to 9O% ee.
Abstract: An asymmetric aza-Diels-Alder reaction of an imines mediated by an in situ generated chiral boron complex is described. The method is successful with several aldimines and affords products of up to 9O% ee
115 citations
TL;DR: Allyl and propargyl-silanes can serve as three-carbon components in a [3+2] annulation strategy for the synthesis of five-membered carbocycles and heterocycles as discussed by the authors.
Abstract: Allyl- and propargylsilanes can serve as three-carbon components in a [3+2] annulation strategy for the synthesis of five-membered carbocycles and heterocycles
113 citations
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93 citations
TL;DR: Palladium-catalyzed carbonylative cross coupling reaction of organofluorosilanes with organic halides was achieved in the presence of fluoride ion and an atmospheric pressure of carbon monoxide as discussed by the authors.
89 citations
TL;DR: In this paper, a convergent, one-pot construction of functionalized pyrrolidine ring system is developed based on a tandem Michael reaction initiated by an intermolecular conjugate addition of a nitrogen nucleophile to an electrophilic olefin followed by trapping of the generated enolate by a built-in α,β-unsaturated acceptor.
Abstract: A convergent, one-pot construction of functionalized pyrrolidine ring systemshas been developed. The method is based on a tandem Michael reaction initiated by an intermolecular conjugate addition of a nitrogen nucleophile to an electrophilic olefin followed by trapping of the generated enolate by a built-in α,β-unsaturated acceptor. After model studis verified the feasibility of the process and gave information about its stereochemical outcome, the strategy was successfully applied to kainoid synthesis
TL;DR: In this paper, the development of a unified synthetic strategy for the indole diterpene tremorgens has led to the first total synthesis of (+)-paspalicine and (+-paspalinine from 4a-methyl octahydro naphthalene-2,5 -dione.
Abstract: The development of a unified synthetic strategy for the indole diterpene tremorgens has led to the first total synthesis of (+)-paspalicine and (+)-paspalinine from 4a-methyl octahydro naphthalene-2,5 -dione
TL;DR: In this paper, the use of catalytic amounts of tetrabutylammonium perrhenate and p-toluenesulfonic acid hydrate for allylic rearrangement and/or dehydration reaction of allylic alcohols is described.
TL;DR: In this paper, photooxygenation of enone 4 with a sun lamp using rose bengal lactone or CuSO 4 as a sensitizer was used to give a mixture of peroxy hemiketals 15 and 16.
Abstract: Seven-step syntheses of the antitumor cyclic peroxy ketals 1a, 2a, chondrillin (1b), and plakorin (2b) from (methoxymethoxy)benzene (8) have been achieved in 26-28% overall yields. The key step is the photooxygenation of enone 4 with a sun lamp using rose bengal lactone or CuSO 4 as a sensitizer which gives a mixture of peroxy hemiketals 15 and 16 in 75-85% yields. Acetal formation in acidic methanol completes the syntheses of 1 and 2. The mechanism of photooxygenation was ascertained using 3-nonen-2-one (22) as a model for 4
TL;DR: In this paper, two independent routes to the CD fragment of vitamin D metabolites and analogues are described, and two independent CD routes are used to obtain the analogues of these metabolites.
Abstract: Two independent routes to the CD fragment of vitamin D metabolites and analogues are described.
TL;DR: In this article, a Lewis acid-mediated enhancement of stereo and regioselectivity has been achieved for the first time in intermolecular nitrone cycloadditions.
TL;DR: In this article, the cycloaddition behavior of 4methoxy-6-methyl-3-oxidopyrylium ylid from α-deoxykojic acid and its cycloadding behavior as a 5 carbon dipole or carbonyl Ylid with various dipolarophiles is described.
TL;DR: Cobalt carbonyl complexes of electron-deficient internal alkynes undergo Pauson-Khand cycloaddition efficiently and regioselectively as mentioned in this paper.
Abstract: Cobalt carbonyl complexes of electron-deficient internal alkynes undergo Pauson-Khand cycloaddition efficiently and regioselectively
TL;DR: In this paper, the synthesis of aldehyde, a ketone or a car-yl on the side chain can be obtained by oxidation of the hydroxyalkylphosphine-borane complexes followed by decomplexation using diethylamine.
TL;DR: In this article, metalated cyclopropenone acetals 5 react with a variety of electrophiles, including alkyl halides, carbonyl compounds, vinyl iodides, vinyl triflates, and aryl iodides.
TL;DR: In this article, the palladium-mediated arylation of peracetylated glycal-derived enones afforded mixtures of C-glycosides containing an arylated enone and an annealed ketone.
Abstract: The palladium-mediated arylation of the peracetylated glycal-derived enones afforded mixtures of C-glycosides containing an arylated enone and an arylated ketone . A rationale for the formation of these compounds is given. Reduction of the arylated enones proceeds in a stereospecific manner, thus affording aryl 2-deoxy-β-D-C-glycopyranosides in high yield
TL;DR: The first total synthesis of the antibiotic (+)-hitachimycin (a.k.a. stubomycin) has been achieved in 22 steps and 1.1% overall yield.
Abstract: The first total synthesis of the antitumor antibiotic (+)-hitachimycin (a.k.a. stubomycin) (1) has been achieved in 22 steps and 1.1% overall yield. The cornerstone of the synthetic strategy was a highly stereoselective three-component coupling of (-)-5-methoxycyclopentenone (4) with a zincate derived from vinyl iodide 3a and aldehyde (-)-51
TL;DR: The isodaucane sesquiterpenes (+)-aphanamol I (3) and (-)-2-oxoisodauc-5-en-12-al[(-)-6] have been prepared in a short reaction sequence from 5(S)-isopropyl 2-methyl 1-cyclopentene-1-carbaldehyde (S)-23 (readily obtainable from (+)-limonene) as discussed by the authors.
Abstract: The isodaucane sesquiterpenes (+)-aphanamol I (3) and (-)-2-oxoisodauc-5-en-12-al[(-)-6] have been prepared in a short reaction sequence from 5(S)-isopropyl-2-methyl-1-cyclopentene-1-carbaldehyde (S)-23 (readily obtainable from (+)-limonene)
TL;DR: In this article, the reaction of benzoyl substituted ketene dithioacetals with various diamines has been studied and the mechansim of formation of these two different products are discussed.
Abstract: Heterocyclic ketene aminals 5 or 3H-1,5-benzodiazepines 4 were obtained from the reaction of benzoyl substituted ketene dithioacetals 1 with various diamines 2. The mechansim of formation of these two different products are discussed.