关键词： Lipids   Aldehydes   Peptides and proteins   Monomers   Organic compounds  

摘要： Discusses the preparation of unsaturated alpha-amino fatty acids in their enantiomeric forms. Information on lipidic acids and their involvement in signal transduction and medicine; Combination of the structural features of amino acids with those of fatty acids; Use of regioselective functionalization in the study; Methodology and results of the study.

关键词： Oxides   High-performance liquid chromatography   Ligands   Stereoselectivity   Sandwich compounds  

摘要： Presents a study which developed an asymmetric synthesis of enantiopure 1,2-disubstituted ferrocene derivatives. Information on the main method used for the preparation of enantiopure ferrocenes; Experimental procedure used in the study; Conclusion of the study.

关键词： Stereoselectivity   Substituents   Catalysts   Hydrogenation   Alkyls  

摘要： Describes an enantioselective synthesis of optically active erythro- and threo-beta-hydroxy-alpha-amino acids by TRAP-rhodium-catalyzed asymmetric hydrogenation of beta-oxy-alpha-acetamidoacrylates. Role of optically active beta-hydroxy-alpha-amino acids in organic synthesis; Description of research methods utilized; Information on enantioselective hydrogenation of (Z)-2a catalyzed by rhodium complex.

关键词： 不对称有机合成   不对称放大反应   不对称合成  

摘要： 概述了不对称放大的提出，不对称放大反应类型，不对称放大反应中关键配合物的结构以及不对称放大的数学模型。

关键词： 双环倍半萜类   天然产物   不对称合成   生物活性  

关键词： VB环B酰亚胺   琥珀酰胺类药物   不对称合成  

关键词： (+)-3-oxacarbacyclin   (+)-3-oxaisocarbacyclin   chiral base   chiral phosphonoacetate   asymmetric synthesis  

摘要： Asymmetric total syntheses of 3-oxacarbacyclin (4) and 3-oxaisocarbacyclin (5) have been achieved by a new and common route. The key step of these syntheses is an enantioselective deprotonation of the prochiral ketone 25 with Lithium (R,R)-bis(phenylethyl)amide (12) in the presence of LiCl. Treatment of the thus formed enolate 26 with ClSiEt3 gave the enol ether 27 of 92% ee in 94% yield. Deprotonation of the analogous prochiral ketone 9 with 12 in the presence of LiCl followed by reaction of the enolate 13 with ClSiEt3 led to isolation of the silyl enol ether 8b of 92% ee in 95% yield. A study of the deprotonation of 9 with the chiral Lithium amides 14-19 showed that 12 in combination with LiCl is the optimal base in terms of enantioselectivity and accessibility. The alpha-side chain in 4 and 5 was established by a Mukaiyama reaction of 27 with the unsaturated aldehyde 28, leading to ketone 39 of 90% de, in combination with a stereoselective Pd-catalyzed allylic rearrangement of acetate 47 to the isomeric acetate 48 and a Mitsunobu reaction of the allylic alcohol 49. The key step in the construction of the alpha-side chain in 4 is a Horner-Wadsworth-Emmons reaction of ketone 7c with the 8-phenylnormenthol-containing phosphonoacetate 56 which gave ester 60 of 90% de. Ester 60 was obtained diastereomerically pure by chromatography in 72% yield from 7c. Reduction of 60 furnished the allylic alcohol 62 which was converted to 4 in a standard fashion. It is at the stage of the alpha,beta-unsaturated ester 60 where divergence into synthesis of 5 was made. Selective isomerization of 60 to the beta,gamma-unsaturated ester 66 of 97% ie in 91% yield was accomplished by deprotonation of 60 with 12 to enolate 65 and its subsequent regioselective protonation. By a similar reaction sequence the isomeric alpha,beta-unsaturated ester 61 was converted to the beta,gamma-unsaturated ester 69 of 97% ie in 88% yield. Reduction of 66 afforded the homoallylic alcohol 71 which was converte

关键词： Ethers   Hydrocarbons   Vinyl   Stereochemistry   Organic reactions  

摘要： Rhodium(II) octanoate catalyzed decomposition of 2-diazo-3-siloxybutenoates, containing (R)-pantolactone as a chiral auxiliary, in the presence of vinyl ethers results in the diastereoselective synthesis of cyclopropanes with high asymmetric induction. Treatment of the cyclopropanes with tetrabutylammonium fluoride results in desilylation and ring expansion of the resulting acylcyclopropanes to 2,3-dihydrofurans with retention of stereochemistry.

关键词： Peptides and proteins   Reaction products   Cyclization   Organic compounds   Olefin metathesis  

摘要： An efficient and versatile method has been developed for the synthesis of a selectively protected 2,7-diaminosuberic acid derivative. A Grubbs ring-closure olefin metathesis reaction was used as a key step on an allylglycine-derived template.

关键词： 氨基酸   不对称合成   热力学   构型熵  

摘要： 从热力学角度分析了氨基酸不对称化学合成中光学收率与构型熵及温度的关系