In vitro germination and shoot proliferation of the threatened species Cinchona officinalis L(Rubiaceae).

Cinchona officinalis （Rubiaceae） is an endemic species of the Loja Valley in southern Ecuador with medicinal uses. Because of over-exploitation in the nine- teenth century and more recent disturbances to its ecosystem, C. officinalis populations are threatened. Currently, natural regeneration of the populations is low, despite its high plant regeneration and seed formation capacity. In the present study, an efficient protocol for germination, shoot proliferation and plantlets regeneration was developed for this species. Phenolic content and germination rate of C. officinalis seeds were compared with a control species, C. pubescens. Nodal segments from seedlings of C. officinalis were cultured on Gamborg medium supplemented with different combinations of plant growth regulators. Because the phenol content is high in C. officinalis, the phenolic should be removed with hydrogen peroxide or water washes to stimulate germination. Shoots and callus developed from nodal segments within 45 days using most of the tested combinations of plant growth regulators. The best rates of shoot proliferation, callus formation and adventitious buds were obtained in medium supplemented with 5.0 mg L^-1 6-benzyl-aminopurine and 3.0 mg L^-1 indole- 3-butyfic acid.

Asymmetric Hydrogenation Synthesis of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic Acid by Cinchona Modified Pd(0)-α-FeOOH Catalyst

Asymmetric hydrogenation of (6-methoxyl-2-naphthyl)-2-acrylic acid catalyzed by cinchona modified Pd(0)-a-FeOOH was reported and ee抯 of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic acid ((S)-(+)-naproxen) up to 98% was achieved firstly.

A convenient microwave-assisted synthesis of cinchona alkaloid-derived ligands

An efficient synthesis of cinchona alkaloid-derived ligands based on solvent-free microwave-assisted reaction was described. The coupling of 1,4-dichlorophthalazine or 3,6-dichloropyridazine with quinine, cinchonine or cinchonidine provide bis-or monocinchona alkaloid-derived ligands in moderate to good yields （52-89%） within 15 min under optimum microwave conditions.

Asymmetric Phase-transfer Mediated Epoxidation of α, β-Enones Using Dendritic Catalysts Derived from Cinchona Alkaloids

Chiral phase-transfer catalysts, derived from cinchona alkaloids and Fréchet dendritic wedges up to generation two, have been synthesized. These chiral dendritic molecules have been used as PTCs in the epoxidation of α, β-enones, showing a moderate level of asymmetric induction.

Computational studies of cinchona alkaloid-catalyzed asymmetric Michael additions

Cinchona alkaloid is one of the most effective organocatalysts that facilitate a wide range of transformations. To elucidate the mechanistic details and especially the origins of the observed high enantio- and diastereoselectivities, computational chemists have contributed dramatic efforts in this important area. This review covers the recent computational studies on the cinchona alkaloid-catalyzed asymmetric Michael additions, including both C-C and C-S bond formations, to present a general viewpoint of these fruitful advances. Based on the types of bond formation and the cinchona alkaloid catalysts, key information regarding the activation model and the origins of enantioselectivities is discussed.

Using Natural Cinchona Alkaloids to Promote the Enantioselective Addition of Dialkylzinc to N-Diphenylphosphinylimines

Cinchona alkaloids are utilized as chiral ligands to promote the enantioselective addition of dialkylzinc to N-diphenylphos-phinylimines affording enantiomerically enriched N-diphenyl-phosphinylamines in up to 91% ee.

Chiral Cinchona Alkaloid-Thiourea Catalyzed Mannich Reaction for Enantioselective Synthesis of β-Amino Ketones Bearing Benzothiazol Moiety

Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alka-loid-derived thiourea. The reactions led to chiral r-amino carbonyl compounds in high yields and good enantiose-lectivities. The study demonstrated for the first time that Mannich reactions of unmodified acetylacetone with het-erocyclic imine derived from benzothiazole can be promoted by chiral bifunctional organocatalyst.

Cinchona Alkaloid-catalyzed Asymmetric Direct Mannich Reaction of Malononitrile to Imine for Synthesis of β-Amino Malononitrile

The first direct asymmetric Mannich reaction of malononitrile to N-Boc-protected imines has been developed with cinchona alkaloid as catalyst. The procedure could tolerate a relatively wide range of substrates, and results in excellent yields and good enantioselectivities even in the presence of only 1 mol% of catalyst loading. The present work provides an easy access to β-amino malononitrile derivatives.

Enantioselective synthesis of β-amino esters bearing a quinazoline moiety via a Mannich-type reaction catalyzed by a cinchona alkaloid derivative

The cinchona alkaloids catalyzed the direct asymmetric Mannich reactions of 1, 3-dicarbonyl compounds with acyl imines to produce novel β-amino ester derivatives containing a quinazoline moiety. The adducts were isolated with high enantiomeric excess （up to 99%）.

A Cu/Cinchona P,N-ligand system enabled general asymmetric C(sp^3)–C(sp) coupling

Due to the special structural feature and versatile reactivity towards various types of transformations,alkynes have inspired continuous research interest for their generation,incorporation and application in organic synthesis,chemical biology and material science[1].Notably,since its invention in 1975,the Sonogashira reaction,which efficiently couples aryl halides with aryl or vinyl terminal alkynes via Pd(0)/Cu(I)synergistic catalysis.

An easy route to exotic 9-epimers of 9-amino-(9-deoxy) cinchona alkaloids with(8S,9R) and(8R,9S)-configurations through two inversions of configuration

Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversions of configuration at the 9-stereogenic centers of commercially available cinchona alkaloids.

A green access to supported cinchona alkaloid amide catalysts for heterogeneous enantioselective allylsilylation of aldehydes and process intensity evaluation in batch and flow

We report herein a new class of polystyrene-supported cinchona alkaloid amide catalysts for enantioselective allylation of various aldehydes using allyltrichlorosilane under both batch and continuous flow conditions.The supported catalyst was synthesized using an environmentally benign coupling agent with a surfactant in aqueous media.Under batch conditions,consistently high yields and enantioselectivity were obtained for the allylation of aliphatic aldehydes with recycling and reuse of the catalyst for more than 10 runs.Subsequently,this catalytic system was successfully implemented into a packed bed flow reactor with similar efficiency and enantiose-lectivity.While flow is a viable option,the batch methodology has better potential for application at a larger-scale setting upon the comparison of space-time yield and catalyst loadings.With the sustainable synthesis and great recyclability of our polymeric catalyst,this methodology holds great potential for the large-scale delivery of valuable enantiopure homoallylic alcohols.

Enantioselective direct aldol-type reaction of 4-hydroxycoumarin with ethyl trifluoropyruvate catalyzed by modified cinchona alkaloids

A new enantioselective aldol-type reaction of 4-hydroxycoumarins and ethyl trifluoropyruvate has been developed. In the presence of (DHQD)2PHAL (5 mol%), ethyl trifluoropyruvate could react with various 4-hydroxycoumarins to afford novel 4-hydroxycoumarin derivatives containing a tertiary trifluoromethyl alcohol center in good yields with moderate enantioselectivities.

有机催化4-羟基香豆素与靛红、丙二腈的不对称Michael加成/环化串联反应

含有杂环的光学活性螺环羟吲哚衍生物因其多种多样的生物活性而备受关注。靛红衍生物的不对称Michael/环化串联反应是构建手性螺环羟吲哚化合物的重要方法。本文将11种有机催化剂用于靛红、4-羟基香豆素与丙二腈的不对称Michael加成/环化串联反应。筛选出最佳的催化剂体系为:10 mol%金鸡纳碱衍生物催化剂1f,二氯甲烷(1 m L)为溶剂,室温反应。将最佳条件用于不同取代靛红的反应,以80~88%的产率和最高达96%的对映选择性获得了螺[羟吲哚-3,4′-吡喃色烯]化合物。本研究拓宽了该反应的催化剂类型和底物范围。

超声法提取金鸡纳生物碱的工艺

研究金鸡纳总生物碱的超声提取工艺.采用L9(34)正交设计通过正交试验得出了超声提取的最佳工艺条件.超声提取的影响因素顺序为提取次数>提取时间>料液比,其最佳提取条件为A2B2C2,即8倍量的甲苯提取液提取4次,每次45 min.实验证明该提取工艺方法经济合理.

高分子支载的金鸡纳生物碱催化剂在不对称催化反应中的应用进展

综述了近年来高分子支载的金鸡纳生物碱催化剂在不对称双羟基化反应、不对称Michael加成反应、活性亚胺的不对称烷基化反应以及潜手性酮的不对称还原反应中的应用及最新进展。

金鸡纳生物碱衍生手性双胺配体的合成及其在不对称氢转移反应中的催化作用

以价廉易得的天然金鸡纳生物碱奎宁和辛可宁为原料,在温和条件下容易地合成了6种手性双胺配体. 考察了它们与过渡金属Ir和Rh形成的配合物在苯乙酮不对称氢转移反应中的催化活性和不对称诱导作用. 结果表明, 9-氨基金鸡纳生物碱配体具有良好的不对称催化活性,而当配体中的氨基被取代后其对映选择性降低. 将9-氨基（9-脱氧）表辛可宁的Ir配合物用于其它芳香酮的不对称氢转移反应时,该配体也显示了很高的催化活性（80%～90%收率）和对映选择性（除对氯苯乙酮ee值为72%外,其余芳香酮ee值均为95%～97%）.

金鸡纳碱衍生物修饰的负载铱催化剂催化芳香酮不对称加氢

以金鸡纳碱衍生物作为手性修饰剂,研究了三苯基膦稳定的Ir/SiO2催化剂催化芳香酮多相不对称加氢.通过电感耦合等离子体原子发射发谱(ICP-AES)、高分辨透射电镜(HRTEM)、X射线光电子能谱(XPS)、Brunauer-Emmett-Teller(BET)比表面积测试等固体表面分析手段对负载铱催化体系进行了表征;利用红外(IR)光谱、固体核磁共振(NMR)等分析手段初步表征了负载铱多相催化体系中手性修饰剂-金属-稳定剂在载体上的相互作用;利用'均相与多相催化体系的对比'、'催化剂稳定性实验'、'汞中毒实验'等方法阐明了手性修饰的负载铱催化体系是多相催化体系.还考察了稳定剂种类、修饰剂种类、金属负载量、溶剂、碱添加剂种类等因素对不对称加氢反应的影响.结果表明,金鸡纳碱衍生物对Ir/SiO2催化剂具有较好的修饰作用,在优化反应条件下苯乙酮及其衍生物加氢反应的对映选择性为52%-96%,4-乙酰基吡啶、2-乙酰基噻吩及2-乙酰基呋喃加氢反应的对映选择性可分别达到74%、75%及63%.

多相不对称催化氢化研究进展

本文综述了多相不对称催化氢化反应的最新研究进展。特别是对最近几年来两个典型的多相不对称催化氢化体系即酒石酸盐修饰镍催化剂催化 β-酮酸酯的不对称氢化反应体系和金鸡纳生物碱修饰铂催化剂催化 α-酮酸酯的不对称氢化反应体系进行了详细的介绍和讨论 ,同时展望了多相不对称催化氢化反应研究的前景。

两种不对称二羟化反应的新型手性配体的合成及其应用

目的 :设计两种新的桥联基以合成两种新的不对称二羟化反应的金鸡纳碱衍生物配体并将其用于催化四种烯烃的不对称二羟化反应 ,考察催化效果 .方法 :以苯酚、α 萘酚和氰尿酰氯为原料 ,制备两种新桥联基 ,然后在氮气保护下 ,于5 0℃分别与奎宁反应生成两个新配体 ,并将其用于锇酸钾 铁氰化钾、H2 O tBuOH(1∶1 )体系 ,催化四种烯烃的不对称二羟化反应 .结果 :结果表明 ,化学产率为 75 %～ 98% ,对映体过量均大于 80 % .结论 :以氰尿酰氯衍生物为桥联基合成的两种奎宁金鸡纳碱衍生物配体 ,方法简便、成本低廉 。