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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 CC 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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Claudio Fuganti Piero Grasselli Stefano Servi Carlo Zirotti 《Tetrahedron letters》1982,23(41):4269-4272
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 (3,4) 4-methyl-3-heptanol (21). 相似文献
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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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Azoalkenes react with enamines and β-dicarbonyl compounds to give -carbomethoxyaminopyrroles rather than -carbomethoxy-1,2-dihydropyridazines. 相似文献
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An asymmetric synthesis of both isomers of dimethyl 2-acetoxycitramalate in over 96% enantiomeric excess is described. 相似文献
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The ∠ 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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Tadashi Nakata Shigeto Nagao Sachiko Takao Tadasu Tanaka Takeshi Oishi 《Tetrahedron letters》1985,26(1):73-74
(1,3,5)-1,3-Dimethyl]-2,9-dioxabicyclo[3.3.1]nonane has been stereoselectively synthesized based on a highly stereoselective method for the synthesis of 1,3--polyol. 相似文献
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Cyclic as well as acyclic ketones, both saturated and α,β-unsaturated, can be converted into their homologous enamines by Horner-Wittig reaction with -methyl--anilinomethyl diphenylphosphine oxide (). 相似文献
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Methods are described for the stereospecific conversion of hydrindenone 3 either to the corresponding fused or fused hydrindanone (1 or 2, respectively.) 相似文献
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N-Acyl derivatives of ,-acosamine and ,-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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the title -acyl-derivatives react with -BuLi and Grignard reagents leading to products, which, formally, can be considered as derived from a Claisen-type condensation reaction. 相似文献
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-Methylthiophthalimide undergoes photochemical cycloaddition reactions with diphenylacetylene, hex-3-yne and bis(methylthio)acetylene to form spiro-thietes; in solution the spiro-thiete from the bis(methylthio)alkyne is in equilibrium with its ring-opened isomer. 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