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Enantioselective synthesis of (R)-α-amino acids via heterocyclic intermediate-(3S)-2,5-dimethoxy-3-see-butyl-3, 6-dihydropyrazine (5), using L-isoleucine as chiral auxiliaryreagent and glycine as raw meterial, has been studied. The alkylation of compound 5 withbutyllithium affords its lithium derivative (6) according to the cardanion mechanism. Then 6reacts with alkyl halide RX (7) to give the alkylated products (8) with very high diastereo-selectivity. In this reaction, the group R of 7 enters trans to the see-butyl group at C-3, i. e.the (R)-configuration is induced at C-6 of 8. After hydrolysis the (R)-α-amino acid methylesters (9) are obtained. 相似文献
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(1R,2S)或(1S,2R)—1,2—二苯基—2—氨基乙醇衍生物手性配体的合成及其用于不 总被引:1,自引:0,他引:1
重点报道了以(1R,2S)或(1S,2R)-1,2-二苯基-2-氨基乙醇衍生物手笥配体的合成及其用于不对称催化反应的研究,如去氢氨基酸的氢化,醛的乙基锌加成,酮的还原,活泼亚甲基化合物的烷基化,醛的硅腈化和瑞福马斯基反应等。研究了手性配体的结构,底物和反件等对上述反应的对映造反性和催化活性的影响。 相似文献
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对一系列手性Salen和唑啉配体与中心金属Cu(Ⅱ)的配合物催化2-苯基环己酮的不对称Baeyer-Villiger反应进行了研究,设计和合成了新型手性配体Ⅲ,Ⅳ, Ⅴ,对配合物Ⅴ-Cu(Ⅱ)进行了单晶X射线衍射分析. 并考察了助氧化剂、溶剂等对反应活性和选择性的影响. 相似文献
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