关键词： 不对称   络合催化   烯烃   二苯乙二酮   奎宁   脂肪族不饱和烃   氮杂环化合物   过渡金属   过渡元素   不对称催化氢化  

摘要： 旋光异构体的合成是有机化学的重要课题。近年发展起来的过渡金属络合催化的不对称合成,是化学方法合成旋光异构体的新的重大的发展,它和酶催化的不对称合成相仿佛,能获得相当高的旋光产率,而仅消耗少量的旋光性试剂。因此不仅在理论上,而且在实用上,如旋光性氨基酸、香料、特别是药物的合成,具有十分重要的意义。

摘要： The Diels-Alder reaction represents a promising tool for use in asymmetric synthesis. The reaction involves a rigid transition state that facilitates the formation of one diastereomeric transition state and is reversible. This satisfies two necessary criteria for asymmetric synthesis. The Diels-Alder reactions of 1,l-dialkylspiro[2.4]-4,6- heptadienes with maleic anhydride and p-benzoquinone in chloroform were studied. The spirodienes were generated by the reactions of 6,6- dialkylfulvenes with dimethyloxosulfonium methylide in dimethyl sulfoxide. Complete facial differentiation of cis-9-tert-butyldispiro[ 4.***.5.1]-1,3-dodecadiene was found in its Diels-Alder reactions with maleic anhydride and p-benzoquinone. Less complete facial differentiation was effected with 1,l-dimethylspiro[2.4]-4,6- heptadiene and dispiro-[4.***.5.1]-1,3-dodecadiene. The Diels-Alder reaction of p-benzoquinone and spiro[2.4]-4,6-heptadiene was found to be reversible at 170°.

摘要： This research work has been planned with the intention of proving the absolute configuration of lactobacillc acid. During the course of this work, attempts have been made to synthesize cis-2-carboxycyclopropane- l-.acetic acid as,v,a suitable resolvable material. As the results were not satisfactory, the synthesis of ci,s-2-carboxycyclopropane-l-propionic acid has been alternatively attempted by ring opening of bicyclo- [4.1.~-heptan-2-onewithout much success. Attempts to resolve or prepare bicyclo[ 4.1.~-hePtan-2-one optically active are also reported. On the other hand, a complete scheme is described for the possible synthesis of optically active lactobacillic acid. If only bicyclo- ~.1.~ -heptan-2-one can be resolved or prepared optically active, this described scheme can be applied smoothly to the synthesis of enant~omeric lactobacillic acid.

关键词： 苏氨酸   产率   苯胺   伯胺   木瓜蛋白酶   析解   外消旋   不对称   氨基酸   氨基羧酸  

摘要： 外消旋苏氨酸可通过多种方法析解,其中有:在DL-苏氨酸饱和水溶液中加入L-或D-苏氨酸,诱导相应的异构体生成结晶;还有利用二甲马钱子碱等与DL-苏氨酸衍生物进行非对映体合成,然后析解的工作。近年来,又有用菌体KT;,KT;,KT;,KT;等无细胞提取液的丙酮粉,不对称水解N-苯甲酰-DL-苏氨酸得到L-苏氨酸的工作;以及用乙酰化酶Ⅰ水解N-氯乙酰-DL-苏氨酸,或N-氯乙酰O-甲基-DL-苏氨酸得到L-和D-异构体的工作。 这些方法中以乙酰化酶Ⅰ法最力成熟,其他方法或由于操作较繁,光学纯度较低,或由于产率太低,皆不能令人满意。

关键词： 苯胺   产率   伯胺   反应   甲氧   酚基   木瓜蛋白酶   析解   正己   酶浓度   外消旋   不对称   丝氨酸   氨基酸   氨基羧酸   酰基  

摘要： 1.在木瓜蛋白酶作用下,N-酰基-DL-丝氨酸与苯胺作用合成了N-异戊酰-、N-正己酰-、N-苯甲酰-及N-苯甲氧羰酰-L-丝氨酸酰苯胺。 2.脂肪族取代基,正己酰-,取代的丝氨酸酰苯胺不对称合成反应的最适pH为4.9～5.1;芳香族取代基,苯甲氧羰酰-,取代的丝氨酸酰苯胺不对称合成反应的最适pH为5.0～5.2。 3.比较了四种酰基-丝氨酸的酰苯胺合成的速度。N-苯甲氧羰酰-L-丝氨酸酰苯胺最快;N-苯甲酰-,N-正己酰-其次;N-异戊酰-最慢。 4.在最适pH,酶浓度自1.31毫克蛋白N/毫升反应液提高到2.27毫克蛋白N/毫升反应液时,N-苯甲氧羰酰-L-丝氨酸酰苯胺的产率,在24小时自76.43％提高到100％。 5.在pH=5.0～5.2,柠檬酸缓冲液浓度自0.2M提高到1.0M时,N-苯甲氧羰酰-L-丝氨酸酰苯胺的产率,在12小时提高了1％。 6.选定了苯甲氧羰酰基为取代基;反应最适pH=5.0～5.2;酶浓度为2.2毫克蛋白N/毫升反应液;缓冲液浓度为0.2M;作为丝氨酸酰苯胺不对称合成的最适条件,在此条件下进行了实际析解,得到中间产物N-苯甲氧羰酰-L-丝氨酸酰苯胺,与此同时,还得到了N-苯甲酰-、N-正己酰-、N-异戊酰-L-丝氨酸酰苯胺。 7.水解N-苯甲氧羰酰-、N-苯甲酰-、N-正己酰-、N-异戊酰-L-丝氨酸酰苯胺,得到了L-丝氨酸,水解N-苯甲氧羰酰-D-线氨酸,得到了D-丝氨酸,两个旋

关键词： 异亮氨酸   异白氨酸   氨基酸   氨基羧酸   木瓜蛋白酶   苯胺   伯胺   析解   不对称   外消旋   酰基  

摘要： 1.对于酰基-(己廾)亮氨酸酰苯胺的木瓜蛋白酶促合成,探讨了(己廾)丁酰,正戊酰,正己酰三 个下同取代基的影响。正戊酰,(己廾)丁酰取代的异亮氨酸酰苯胺的不对称合成可定量地进行。正戊酰衍生物的合成速度比(己廾)丁酰衍生物要快,(己廾)丁酰衍生物又快于正己酰衍生物。 2.(己廾)丁酰,正戊酰(己廾)亮氨酸酰苯胺合成的最适pH是5.1～5.3。 3.通过正戊酰基(或(己廾)丁酰基)的取代,及木瓜蛋白酶促酰苯胺的不对称合成,有效地析解了外消旋(己廾)亮氨酸,得到L—(己廾)亮氨酸,还得到了中间产物:(己廾)丁酰和正戊酰L—(己廾)亮氨酸酰苯胺。 4.对于酰苯胺的两种测定方法(直接的重量法及间接的苯胺滴定法)进行了此较和讨论。

摘要： In this thesis, a systematic review of chiral phosphines and hydrophosphination reactions are described in Chapter 1. This chapter reviews the significance of chiral phosphines and their classification: chiral phosphines with P- chiral center(s), with chiral center(s) in the side-chain or axial chirality in the side- chain and chiral phosphines based on ferrocene. Their synthetic strategies are also discussed. In addition, acid catalyzed-, base catalyzed-, free radical mediated-, transition metal catalyzed-, transition metal complex promoted- and organocatalytic-hydrophosphination reactions are demonstrated. In Chapter 2, a novel chiral resolution of the diphosphine ligand diethyl-1,2- bis-(diphenylphosphino)-ethanedicarboxylate with the assistance of an optically active palladium(II) template is thoroughly investigated. Through the interconversion of cationic diastereomeric mixtures from metal complexation, the optically active diphosphine was obtained in high yield. In Chapter 3, an organopalladium(II) complex derived from (5)-N, N- dimethyl-1-(1-naphthyl)-ethylamine as the chiral auxiliary has been used to promote the asymmetric hydrophosphination reactions between diphenylphosphine and (E) or (Z)-diphenylphosphinostyrene in high regio- and stereoselectivities at low temperature with triethyl amine as external base. Optically active free ligand (7?)-l,2-bis(diphenylphosphino)-l-phenylethane was obtained in high yield subsequently. Mechanistic pathways explaining the stereoselectivity of the chiral organopalladium template promoted hydrophosphination reactions are also proposed. In Chapter 4, an organopalladium complex containing ortho-metalated- (R)- (1 -(dimethylamino)ethyl)naphthalene as the chiral auxiliary has been used to promote the asymmetric hydrophosphination reactions between diphenylphosphine and phenyldi[(Z)-prop-l-enyl]phosphine or phenyldi[(2T)-prop-l-enyl]phosphine m high regio- and stereoselectivity under mild conditions. The hydrophosphination pr

摘要： Part I. The first asymmetric synthesis of a-allyl-a-aryl a-amino acids by means of a three component coupling of a-iminoesters, Grignard reagents, and cinnamyl acetate is reported. Notably, the enolate from the tandem process provides a much higher level of reactivity and selectivity than the same enolate generated via direct deprotonation, presumably due to differences in the solvation/aggregation state. A novel method for removal of a homoallylic amine protecting group delivers the free amine congeners. The a-allyl moiety offers a means to generate further valuable a-amino acid structures. Cross-metathesis of the tandem product provided allylic diversity not afforded in the parent reaction. Cyclic a-amino acid derivatives could be accessed by ring closing metathesis presenting a viable strategy to higher ring homologues of enantioenriched a-substituted proline. The 8-member proline analog was successfully converted to the pyrrolizidine natural product backbone. Part II. The asymmetric spirocyclization of allenyl ketones is reported. High-throughput experimentation by means of a chiral Lewis acid library enabled the determination of a suitable catalyst system. Protecting group manipulation provides an orthogonal route to enantioenriched para-quinone and ortho-quinone spirocycles. This novel technology provides access to the spirocyclic core that is prevalent in many natural products. Part III. Palladium has been identified as a suitable catalyst for the chemoselective activation of C(sp3)-H bond over C(sp2)-H bond of toluene and tolyl analogs. This technology has been combined with the C(sp3)-H activation of acidic C-H bonds to form new C-C bonds. High-throughput experimentation was used for identifying conditions that reduced toluene loading and engendered catalyst turnover via a suitable oxidant. The parent reaction has been extended to include the Pd catalyzed alkylation of phenylglycine azlactones with ethylbenzene, 2-ethylnaphthalene, propylbenzene and butylbe