亚甲胺叶立德与环丙基亚甲基乙酸乙酯参与的催化不对称exo-1,3-偶极环加成反应构建5-氮杂-螺[2,4]庚烷片段

首次研究了Cu（CH₃CN）₄BF₄/DTBM-BIPHEP催化的亚甲胺叶立德与环丙基亚甲基乙酸乙酯参与的不对称1,3-偶极环加成反应,获得了优异的exo-选择性,研究结果证实大空间位阻的手性双膦配体对反应的非对映选择性控制起到至关重要的影响;同时一步高效构建三个叔碳手性中心和一个螺环季碳中心. 该不对称1,3-偶极环加成反应收率良好,得到优秀的非对映（>98：2,dr）与对映选择性（ee值高达99%）. 该催化体系为合成exo构型的5-氮杂-螺[2,4]庚烷衍生物提供了一种简洁高效的方法,具有原子经济性好、反应条件温和、底物适用范围广等优点.     

Sm(Ⅲ)催化的三级环氧醇高度非对映选择性重排还原 反应-1, 3-二醇单酯的新 合成方法

本文报道了一个α-羟基环氧化物被Sm(Ⅲ)催化的新颖的串联反应。此反应一步完成了两个连续反应,高度非对映选择性地构筑了三个连续的立体中心。它可以成为一种高度非对映选择性地构筑2-季碳-1,3-二醇结构的一般方法。该反应的条件和机理在文中也作了详细的讨论。     

(R)-α-烷基糠胺的不对称合成

本文通过(+)-樟脑缩呋喃甲亚胺的不对称烷基化反应,合成了(R)-α-烷基糠胺。反应的非对映选择性经~1H NMR测定为5～67％(d.e.).用1,3-二碘丙烷和α,α-二溴邻二甲苯作烷基化试剂,得到预期的双亚胺烷基产物,而用1,2-二溴乙烷时,却给出偶联产物。     

钯催化α-重氮芳基乙酸酯对苯酚O—H键的不对称插入反应

钯催化剂是一类重要的金属催化剂,在有机合成中应用非常广泛.过去几十年里,钯催化的不对称反应也取得了巨大的成就,但是,对于卡宾转移这类非常重要的有机反应,很少有钯催化剂能够给出高对映选择性.最近,南开大学化学学院周其林和朱守非带领课题组实现了首例钯催化不对称O—H键插入反应,获得了很高的对映选择性(最高达到99%ee).这类钯催化不对称卡宾转移反应首次实现了重要手性砌块α-芳氧基苯乙酸衍生物的不对称催化合     

大位阻、富电子MOP型烷基膦配体在钯催化的1,3-二羰基化合物 α-芳基化反应中的应用

富电子、大位阻MOP型烷基膦配体2-二叔丁基膦-2’-异丙氧基-1,1’-联萘(L1)在钯催化的1,3-二羰基化合物的α-芳基化反应中显示了较好的催化活性. 在这类催化反应中, 碱的选择具有重要的影响: 以K3PO4为碱, Pd(OAc)2/L1催化体系在丙二酸二乙酯的α-芳基化中, 富电子溴代芳烃显示较好的活性; Pd(OAc)2/L1催化的乙酰乙酸乙酯α-芳基化时, 以 K2CO3为碱, 催化体系显示较好的活性, 这个催化体系可控制反应得到α-芳基乙酰乙酸乙酯, 而不是脱乙酰基的产物. 较为惰性的氯代芳烃在Pd(OAc)2/L1的催化下, 也能够跟1,3-二羰基化合物发生α-芳基化反应.     

催化剂控制的可调控的化学和非对映选择性:靛红衍生的Morita-Baylis-Hillman碳酸酯的环化反应

正Angew.Chem.Int.Ed.2016,55,2147~2151通过催化剂控制反应的化学或非对映选择性是不对称催化的研究热点,能够以相同的原料在相似的反应条件下生成不同产物,从而提高合成效率;而在反应中能够同时实现化学和非对映选择性的调控、构建多样性手性化合物是一项极具挑战性的工作.四川大学华西药学院陈应春课题组使用不同手性Lewis碱,在催化靛红衍生的MoritaBaylis-Hillman碳酸酯和2-亚烷基-1,3-茚二酮的环化反应中成功地实现了化学选择性和非对映选择性的调控.手性     

钯催化 1,3-丁二烯羧酯化合成 3-戊烯酸甲酯

 以 1,3-丁二烯、CO 和甲醇为原料, 进行羧酯化反应合成 3-戊烯酸甲酯是 Altam 路线生产己内酰胺绿色工艺的关键步骤. 将 Pd 与三齿 N-杂环配体或双膦配体组成的催化体系用于 1,3-丁二烯的羧酯化反应中, 其中乙酸钯/2,6-二 (3,5-二甲基吡唑基) 吡啶催化剂表现出中等的催化活性, 在 150 ºC, p(CO) = 6.0 MPa 的优化条件下反应 6 h, 1,3-丁二烯转化率为 78.8%, 3-戊烯酸甲酯选择性达 92.2% (TON = 226); 而乙酸钯/2,2?-二 (二苯基膦基) 苯醚催化体系的活性更高, 在优化反应条件下, 1,3-丁二烯转化率达 90.4%, 3-戊烯酸甲酯选择性为 91.6% (TON = 181). 在 200 ºC 及类似的羧酯化反应条件下, 1,3-丁二烯发生二聚反应, 其转化率为 99% 以上, 二聚产物 4-乙烯基-1-环己烯选择性高于 96%.     

手性方酰胺催化环状1,3-二羰基化合物对β,γ-不饱和-α-酮酯的不对称Michael加成反应（英文）

发展了新型手性双功能叔胺-方酰胺催化的环状1,3-二羰基化合物和β,γ-不饱和-α-酮酯之间的不对称Michael加成反应,反应条件温和,底物适用范围广泛,相应产物的产率和对映选择性分别高达97%和97%ee,为合成和医药上极为重要的手性色烯衍生物的立体选择性合成提供了一种实用的方法.     

利用1,2-叠氮迁移策略合成β-氟烷基叠氮化合物

化学键选择性断裂与重组是有机分子骨架重塑的基础[1],官能团迁移反应是实现化学键断裂以及形成的重要方式[2~4].虽然已知众多官能团都可以发生迁移反应并且相关研究也取得显著发展,但是叠氮基团的迁移反应报道仍然极为有限[5].到目前为止,仅有Winstein小组于1960年报道了首例烯丙基叠氮的[3,3]-σ重排反应;但是,该反应中生成的是一组异构体混合物,因此缺乏合成上的实用性(Scheme 1A)[6].2017年,Topczewski小组[7]对这一反应的选择性进一步研究:利用Sharpless双羟化反应动力学拆分方式,实现了选择性的1,3-烯丙基叠氮重排反应,得到了单一的异构体产物.     

基于α-溴代酮的催化不对称合成3,3-螺环丙基吲哚酮和乙烯基环丙烷

在甲基化奎尼丁(20mol%)的催化下,分别实现了α-溴代酮与3-(取代亚甲基)吲哚酮和缺电子1,3-二烯的高度非对映选择性和对映选择性的环丙烷化反应,以46%~99%收率、高达98%ee和20∶1 dr生成相应的3,3-螺环丙基吲哚酮和乙烯基环丙烷.通过催化的氮叶立德策略,成功发展了一种用于上述手性化合物的简便合成方法.     

Tetracyanoethylene pi-complex chemistry. Indirect spectrophotometric determination of Diels-Alder-active 1,3-dienes

An indirect spectrophotometric method, based on the rapid Diels-Alder reaction between cisoid 1,3-dienes and tetracyanoethylene (TCNE) and the destruction of an aromatic-TCNE pi-complex, was developed to determine eleven 1,3-dienes in the 0.05-1.00 x 10(-3)M range. These dienes were: cyclopentadiene; 1,3-cyclohexadiene; trans-1,3-pentadiene; 2,4-dimethyl-1,3-pentadiene; trans-2-methyl-1,3-pentadiene; 2-methyl-1,3-butadiene; 9-methylanthracene; 9,10-dimethylanthracene; 1,6-diphenyl-1,3,5-hexatriene; 2,3-dimethyl-1,3-butadiene; and 1,4-diphenyl-1,3-butadiene. Three 1,3-dienes were determined in the 0.05-1 x 10(-4)M range: cyclopentadiene, trans-2-methyl-1,3-pentadiene, and anthracene. The limit of detection for cyclopentadiene in carbon tetrachloride solutions is 0.11 microg/ml. Fourteen 1,3-dienes were found to form stable pi-complexes and could not be determined by the proposed method. For these 1,3-dienes, the spectra of some of the complexes are reported; in addition, relative equilibrium constants for the pi-complexes of 2,5-dimethyl-2,4-hexadiene, cis-1,3-pentadiene, 4-methyl-1,3-pentadiene, and 1,3-cyclo-octadiene were estimated. An explanation of the transient colour in the 1,3-diene-TCNE Diels-Alder reaction is suggested.     

Oxidation of 1,3-Dioxacyclanes with Oxone and Potassium Persulfate Catalyzed by 2,2,5,5-Tetramethyl-4-Phenyl-3-Imidazoline-3-Oxide-1-Oxyl

The catalytic effect of 2,2,5,5-tetramethyl-4-phenyl-3-imidazoline-3-oxide-1-oxyl on the oxidation of 2-isopropyl-1,3-dioxolane, 2-phenyl-1,3-dioxolane, 2-phenyl-4-chlormethyl-1,3-dioxolane, 2-isopropyl-1,3-dioxane, 2-isopropyl-4-methyl-1,3-dioxane, 2-phenyl-1,3-dioxane, 2-phenyl-4-methyl-1,3-dioxane with oxone and potassium persulfate is reported. The corresponding glycol monoesters were obtained with yields of 90-100%.     

New chemical access for pyran core embedded derivatives from bisalkenylated 1,3-diketones and 1,3-diketoesters via tandem C-dealkenylation and cyclization

New chemical access has been developed for the synthesis of pyran core embedded derivatives from 1,3-diketones and 1,3-diketoesters, in which the active methylene group of 1,3-diketone or 1,3-diketoester was alkenylated with three equivalents of alkenyl bromides in presence NaH to give bisalkenyl 1,3-diketones or 1,3-diketoesters and the resultant bisalkenyl 1,3-diketones or 1,3-diketoesters were reacted with AlCl₃ at room temperature to furnish pyran core embedded derivatives in good to excellent yields.     

Synthesis and photoluminescence properties of BF2 complexes with 1,3-diketone ligands

BF₂ complexes with 1,3-diketone ligands were synthesized, and their optical and electrochemical properties were studied. The colors of the complexes varied depending on the structures of the 1,3-diketone ligands. The absorption and emission maxima of the complexes with 1,3-diaryl-1,3-diketone ligands were considerably red shifted as compared to those of the complexes with 1-aryl-3-trifluoromethyl-1,3-diketone ligands, suggesting an extended π-conjugation of the 1,3-diaryl-1,3-diketone moieties. The molar absorption coefficients and quantum yields of the complexes with 1,3-diaryl-1,3-diketone ligands were larger than those of the complexes with 1-aryl-3-trifluoromethyl-1,3-diketone ligands. Cyclic voltammetry measurements revealed that the reduction potentials of the BF₂ complexes were higher than those of the free ligands. These complexes exhibited various emission colors in the solid states due to the intermolecular interactions.     

Skeletal isomerism within 1,3-disilabicyclo[1.1.0]butane and 2,3-disilabuta-1,3-diene derivatives

A bis-adamantane-spiro-fused 1,3-bis(triisopropylsilyl)-1,3-disilabicyclo[1.1.0]butane equilibrates with the corresponding 2,3-bis(triisopropylsilyl)-1,3-disilabuta-1,3-diene with a ratio of 1:19. The 1,3-disilabuta-1,3-diene was fully characterized by a combination of multinuclear NMR and UV-VIS spectroscopies, elemental analysis, and single-crystal X-ray diffraction analysis.     

A convenient one-pot synthesis of substituted 2-pyrone derivatives

2-Pyrone derivatives were prepared in a one step procedure from readily available (chlorocarbonyl)phenyl ketene and 1,3-diketones such as 2,4-pentanedione, 1,3-diphenyl-1,3-propanedione, 1-phenyl-1,3-butanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dimethyl-pyrimidine-2,4,6-trione and ethyl 2,4-dioxopentanoate. A mechanism is presented to account for the formation of the products. This method provides an easy route to prepare 3,4,5,6-tetrasubstituted 2-pyrones in good to excellent yields and in a short experimental time.     

Condensation of 1,3-diketones with 1,8-diaminonaphthalene: Synthesis ofbis(2,3-dihydroperimidine-2-spiro)cycloalkanes

Summary Cyclic 1,3-diketones like cyclopentane-1,3-dione, cyclohexane-1,3-dione, and 5,5-dimethylcyclohexane-1,3-dione react with 1,8-diaminonaphthalene to afford new condensed heterocyclic spiro systems.

---

Kondensation von 1,3-Diketonen mit 1,8-Diaminonaphthalin: Synthese vonBis(2,3-dihydroperimidin-2-spiro)cycloalkanen

Zusammenfassung Cyclische 1,3-Diketone wie Cyclopentan-1,3-dion, Cyclohexan-1,3-dion und 5,5-Dimethylcyclohexan-1,3-dion reagieren mit 1,8-Diaminonaphthalin zu neuen kondensierten heterocyclischen Spiranen.

     

Synthesis of New 1,3-Thiazolecarbaldehydes

H-Lithiation and Br-lithiation reactions of 1,3-thiazole were studied in order to obtain new thiazole derivatives. Four isomeric chloromethyl derivatives of 1,3-thiazole containing a protected aldehyde group like 2-(1,3-dioxolan-2-yl)-5-(chloromethyl)-1,3-thiazole, 5-(1,3-dioxolan-2-yl)-2-(chloromethyl)-1,3-thiazole, 4-(1,3-dioxolan-2-yl)-2-(chloromethyl)-1,3-thiazole, and 2-(1,3-dioxolan-2-yl)-4-(chloromethyl)-1,3-thiazole were synthesized. Their nucleophilic substitution reactions with dimethylamine and sodium methylthiolate were studied. New aldehydes of 1,3-thiazole series of low-molecular weight were obtained.     

Photocyclization of 2-chloro-substituted 1,3-diarylpropan-1,3-diones to flavones

The photochemical behavior of 2-halo-substituted 1,3-diarylpropan-1,3-dione strongly depends on the nature of the halogen atom bonded and the presence of electron-donor groups on the phenyl ring. In the case of 2-chloro-1,3-diphenylpropan-1,3-dione and 1-(3,5-dimethoxyphenyl)-3-phenylpropan-1,3-dione, cyclization to flavones was the sole reaction pathway, whereas in the case of 2-chloro-1,3-di(4-methoxyphenyl)propan-1,3-dione, only products derived from alpha-cleavage were observed. 2-Fluoro derivatives of 1,3-diarylpropan-1,3-diones were photostable; on the other hand, 2-chloro-2-fluoro derivates resulted in 3-fluoroflavones.     

New Approach to the Synthesis of 1,3-Chloroisothiocyanatoalkanes. Synthesis of Tetrahydro-1,3-thiazine-2-thiones and 2-Alkylamino-5,6-dihydro-1,3-thiazines

A method was developed to prepare 1,3-chloroisothiocyanatoalkanes by reducing 1,3-isothiocyanato ketones using sodium borohydride at pH ~7 and subsequent treatment of the resultant 1,3-isothiocyanato alcohols with thionyl chloride. The reaction of 1,3-chloroisothiocyanatoalkanes with sodium hydrosulfide or amines gives substituted tetrahydro-1,3-thiazine-2-thiones or 2-amino-5,6-dihydro-1,3-thiazines.