Showing papers in "European Journal of Organic Chemistry in 1992"

TL;DR: In this article, a test based on kinetic resolution was applied to probe the configurational stability of various α-substituted benzyllithium compounds and it was found that the trimethylsilyl- (1b), phenylsulfenyl-(1c), and the phenylselenyl (1d) compounds enantiomerized more rapidly than they added to the chiral aldehyde 6.

TL;DR: In this paper, the synthesis of 1-Aryl and 1-Alkenyl-β-carbolines by Palladium-catalyzed coupling reactions of 6 with aryl boronic acids is described.

TL;DR: In this paper, 1-propargyl-benzotriazole (16) undergoes lithiation first at the acetylenic CH and then at the CH2 group.

TL;DR: The mixed open-chain imide N-(3-chloro-4-hydroxyphenyl-acetyl)fumarate (1), named coniothyriomycin, was isolated as metabolite of the fungus Coniothyrium as mentioned in this paper.

TL;DR: The solvatochromisms of Michler's ketone and the iron-II complex Fe(phen)2(CN)2 (2) have been investigated in 73 solvents of different polarity as mentioned in this paper.

TL;DR: In this paper, a new inhibiting metabolite from gliding bacteria, thiangazole (1), was detected and isolated using a biological screening with a HIV-1/MT-4 cell assay indicating antiviral activity and cell toxicity.

TL;DR: In this article, the authors reported on the isolation and structure elucidation of the phenalamides A1 (1), A2 (2), A3 (3), B (4), and C (5), amides from alaninol and ω-phenyl-substituted unsaturated carboxylic acids.

TL;DR: In this paper, a two-step procedure for the preparation of a series of lactone-type bridged biaryls 7 as favorable substrates for subsequent atropisomer-selective ring-opening reactions is described.

TL;DR: In this paper, a cycloaddition of methyl α-nitrosoacrylate to silyl enol ether gave 1,2-oxazine and nitrone as byproduct.

TL;DR: In this article, the rate of enantiomerization of methylbenzyllithium (6) was found to be faster than its addition to the amide 7, the ketone 8, or to the aldehyde 10, according to a test based on kinetic resolution.

TL;DR: The natural and (+)-enantiomer of grandisol [1, (1R, 2S)-(+)-2-isopropenyl-1-methylcyclobutaneethanol] has been synthesized from (R)-(−)-carvone (2) by employing the intramolecular alkylation of 8 to give 9 as the key step as discussed by the authors.

TL;DR: In this article, the key step of the synthetic sequence is an intramolecular Nicholas reaction of 17 to give the bicyclo[7.3.1]diyn-10-one dicobalthexacarbonyl adducts 18a and 18b (66% total yield).

TL;DR: The title compounds 5a-c and 7a-m have been prepared by Vilsmeier formylation of 4-aminocoumarins 1 yielding aldehydes 2, and subsequent condensation of 2 with C-H acids in the presence of piperidine as mentioned in this paper.

TL;DR: In this article, the reaction of allylmagnesium chloride with nitrone 1 derived from D-glyceraldehyde affords two diastereoisomeric homoallylic hydroxylamines 2a and 3a which, after separation and O-silylation, are subjected to iodocyclization using N-iodosuccinimide.

TL;DR: In this paper, the synthesis of symmetric and asymmetric dimethoxybipyridines and their corresponding diols are described and compared with those of the corresponding non-symmetric bipyridine derivatives.

TL;DR: In this article, the enantiomeric purity of (S)-3-phenyllactic acid derivatives was shown to be greater than 96% ee.g., the (S) 3-4-dihydroxy-phenyl) lactate (15b) and the methyl 2-benzopyran-3-carboxylates (15c).

TL;DR: The base-promoted reaction of tetra-O-benzyl-glucose 1a with secondary alkyl trifluoromethanesulfonates 2 and 3 in toluene provides in the presence of 15-crown-5 preferentially β-glycosides 2aβ and 3aβ, respectively, in high yields as discussed by the authors.

TL;DR: In this article, 4-Azido-3-coumarincarbaldehydes 2a-d are used starting materials for synthesizing 3,4-disubstituted coumarins as well as heterocyclic [c]-fused coumarin.

TL;DR: The conjugated esters 5, 6, 8, 9 mentioned in the title are prepared from the corresponding aryl acetate 4 and aldehydes by aldol condensation as mentioned in this paper.

TL;DR: In this article, a novel synthesis for thiosugars starting from achiral compounds by using enzymes as catalysts is described, which can be expressed as a deterministic approach.

TL;DR: The synthesis of globotriaosylceramide was based on O-galactosyl trichloroacetimidate 5α as donor and 4b-O-unprotected lactose 7 as acceptor and the use of the inverted procedure for glycoside-bond formation afforded preferentially trisaccharide 8α.

TL;DR: In this article, the authors synthesize α-trifluoromethyl-substituted heterocyclic α-amino and α-hydroxy acid derivatives.

TL;DR: In this paper, the solvent effects on the endo/exo product ratio of the [2 + 2]-photocycloaddition were investigated, and the key step of the synthesis is the Cu(I)-catalyzed [2+ 2]-Photocyclogenesis of 3 to 4a or 4b.

TL;DR: The preparativeenzymatic synthesis of s-L-fucose-1-phosphate as well as its enzymatic conversion into GDP- fucose, an important component of complex heterooligosaccharides, is described.

TL;DR: Feeding experiments on Streptomyces albus produced oxazolomycin (1), whose NMR analysis provided information about the biogenetic construction of its carbon skeleton, and the use of glycine predicts an uncommon biosynthetic pathway leading to oxazole rings in actinomycetes.

TL;DR: In this paper, the regioselectivity in cyclofunctionalization of some acyclic olefinic alcohols with benzeneselenenyl halides (PhSeCl and PhSeBr) at different temperatures (−78°C, O°C and room temperature) is investigated.

TL;DR: Optically active crown ethers 1a, 1o,2, 3a, 2, 4a, 4b, 5a, 5d, 6a, b and acyclic analogue 7 were used for three Michael-type additions, benzoin condensation, a C-alkylation, a base-catalyzed autoxidation and a hypochlorite epoxidation.

TL;DR: In this paper, a new, efficient synthesis of fagomine using yeast transketolase (EC 2.2.1)-catalyzed reaction of racemic 3-hydroxy-4-oxobutyronitrile [(R/S)-2] with lithium hydroxypyruvate (3).

TL;DR: In this article, a large amount of (2R,4R,6R,8R)-2,4,6,8-tetramethyldecanoic and -undecanoisic acid methyl esters were obtained after transesterification and Spaltrohr® distillation of the domestic goose.