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1.
All four isomers of substituted 3-alkylthio-4-hydroxybutenes have been synthesised: both the geometry of the double bond and the relative stereochemistry of the two chiral centres are controlled.  相似文献   

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The identity of 3-oxo-13-tetradecenal as a major component of the Rhinotermeshispidus defense secretion is established by MS, 1H and 13C-NMR, and total synthesis.  相似文献   

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N-Acyl derivatives of D,L-acosamine and D,L-ristosamine were synthesized with high stereo selectivity utilizing intramolecular Michael addition of γ- and δ-carbomoyloxy-α,β-unsaturated esters.  相似文献   

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J Leitich 《Tetrahedron letters》1980,21(32):3025-3028
The relative rates of formation of cis and trans [2+2]cycloadducts of benzyne to cis, trans- and cis, cis-1,5-cyclooctadiene, trans- and cis-cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described.  相似文献   

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Four novel fusicoccane diterpenoids, fusicoplagins A, B, C, and D, have been isolated from the liverwort Plagiochilaacanthophylla subsp. japonica and the structures determined by spectroscopic methods, chemical transformations, and X-ray crystallographic analysis.  相似文献   

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Methods are described for the stereospecific conversion of hydrindenone 3 either to the corresponding trans fused or cis fused hydrindanone (1 or 2, respectively.)  相似文献   

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Starting from the coupling reaction of alkyl cuprates with 1-alkynyl-2-propenyl acetates, the title compounds were prepared by short convenient syntheses.  相似文献   

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The EZ equilibrium of the cations of benzo hydroxamic acids, in mineral acid, was studied utilizing 1H NMR spectroscopy, NOEDS and MNDO claculations  相似文献   

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The C4erythro and threo diols (7) and (8) are converted either into the chiral epoxides (13) and (15) or into the enantiomers (14) and (16); the epoxide (13) is used as chiral synthon for the preparation of (3S,4S) 4-methyl-3-heptanol (21).  相似文献   

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Palladium catalysed alkoxycarbonylation of heterocyclic halides affords a simple and versatile synthesis of both N and S heterocyclic esters where a range of catalysts have been studied and a method to employ inexpensive inorganic bases has been found.  相似文献   

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Reaction of Ga(CH3)3 with N,N′-dimethyloxamide affords two isomeric N,N′-bis(dimethylgallium)-N,N′-dimethyloxamide complexes, characterized by crystal structure analysis as having cis-and trans-configuration with respect to the central oxamide CC bond and belonging to the point groups C2v (cis) and C2h (trans), respectively. Both isomers which are formed in varying ratio, depending upon the reaction conditions, have been isolated in pure form; their vibration spectra (IR/RE) are analyzed in detail in points of alternative behaviour, and are assigned in all bands, especially in the G-C and Ga-X frequency region. The assignment receives further confirmation from a comparison with the vibrational data of the homologous N,N′-bis(dimethylgallium)oxamide (cis/trans isomer mixture).  相似文献   

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