Palladium-catalyzed Cascade Cyclization-Coupling Reaction of Benzyl Halides with N, N-Diallylbenzoylamide

A novel type of palladium-catalyzed cascade cyclization-coupling reaction has been found. Reaction of N, N-diallylbenzoylamide 1 with benzyl halides 2 afforded the corresponding dihydropyrroles 3 in moderate to excellent yields.

Synthesis of Asymmetric 4H-1, 3, 2-Benzodioxaphosphorin 2-Sulfides from Intramolecular Cyclization Reaction

Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of H-1 NMR, P-31 NMR and x-ray diffraction analysis.

Studies on the cyclization reaction of D-aspartic acid

The cyclization reaction of D-aspartic acid was studied, the carboxyl groups of D-aspartic acid were protected by benzyl alcohol to give compound D-dibenzyl aspartate. Then （4R）-benzyl azetidine-2-one-4-carboxylate and meso-3,6-disubstituted piperazine-2,5-diones were synthesized via intramolecular cyclization and intermolecular cycfization of D-dibenzyl aspartate, respectively, and their structures were confirmed by ^1 H NMR and MS. Both cyclization reaction conditions were also investigated in detail.

The Cyclization Reactions of Lawesson's Reagent with Bifunctional Substrates

The cyclizaion reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups, has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-membered phosphorus heterocycles.The heterocyclizaional possibility of LR with bifunctional compounds was also discussed.

Metal-Free Synthesis of 2-Aminobenzothiazoles via I2-Catalyzed Tandem Cyclization Reaction of Amines and Carbon Disulfide

Comprehensive Summary,A convenient approach for the construction of 2-aminobenzothiazoles via I2-catalyzed tandem cyclization reaction of amines and carbon disulfide has been developed.The present approach starts from simple and readily available starting materials,affording a series of 2-aminobenzothiazoles in up to 89%yields under metal-free conditions.In this work,C—H/N—H functionalization was achieved and multiple C-hetero bonds were successfully constructed in one pot.

Construction of Spirooxindole Skeleton Through Intramolecular Dieckmann Cyclization

A highly efficient and direct approach was developed to construct the structurally diverse spirooxindole skeleton,which is an important basic motif in natural products.Both the 3,30-pyrrolidonyl spirooxindoles and spiroindolin-2-one dlactones were 2smoothly obtained by the intramolecular Dieckmann cyclization of oxindoles in excellent yield under mild conditions.

Competition between C-C and C-H Activation in Reactions of Neutral Nickel Atom with Cycloalkanes （n = 3-7）

A theoretical investigation of the reaction mechanisms for C-H and C-C bond activation processes in the reaction of Ni with cycloalkanes C,,H2. （n = 3-7） is carried out. For the Ni ＋ CnH2, （n = 3, 4） reactions, the major and minor reaction channels involve C-C and C-H bond activations, respectively, whereas Ni atom prefers the attacking of C-H bond over the C-C bond in CnH2n （n = 5=7）. The results are in good agreement with the experimental study. In all cases, intermediates and transition states along the reaction paths of interest are characterized, It is found that both the C-H and C-C bond activation processes are proposed to proceed in a one-step manner via one transition state. The overall C-H and C-C bond activation processes are exothermic and involve low energy barriers, thus transition metal atom Ni is a good mediator for the activity of cycloalkanes CnH2n （n = 3 -7）.

新型吡咯[3,4-b]喹啉-1-酮衍生物的简便合成

报道以2-氯甲基喹啉-3-羧酸乙酯为底物,通过与各种芳胺及脂肪胺类化合物在乙醇-乙酸(10:1,v/v)的混合溶剂体系中,经连续的亲核取代和分子内的亲核环化反应过程,一步合成了一系列新型的N-取代-2,3-二氢-1H-吡咯[3,4-b]喹啉-1-酮类化合物.该合成方法具有实验操作简便,反应条件温和,后处理简单和产率高等优点,具有很好的实际应用价值.

苯乙酮一锅法合成吡唑类化合物

吡唑类化合物广泛存在于医药,农药以及功能材料分子之中,同时也是非常有价值的有机合成中间体。本论文研究了在无过渡金属催化条件下,苯乙酮衍生物与N,N-二甲基甲酰胺二甲缩醛反应合成相应的烯胺酮中间体,烯胺酮中间体与水合肼一锅法反应高效合成吡唑类化合物。该环化反应具有合成步骤少,反应产率高,不使用昂贵过渡金属和配体等优点。所合成的吡唑产物经过气相色谱-质谱和核磁共振等进行数据表征和结构鉴定。

Electrochemical Dearomative Spirocyclization of N-Acyl Sulfonamides in a Continuous-Flow Cell

The development of efficient and sustainable methods to obtain spirocyclic compounds is of significance as these structures are widely found in pharmaceuticals and agrochemicals.Herein,we disclose an electrochemical dearomative spirocyclization of N-acyl sulfonamides in a continuous-flow cell.The reaction is simple and efficient without external catalysts or supporting electrolytes and could be applied in a decagram-scale synthesis.

可见光促进三组分合成C3-芳甲基取代的咪唑并[1,2-a]吡啶衍生物

C3-芳甲基取代的咪唑并[1,2-a]吡啶衍生物在材料及药物化学领域有着广泛应用。基于自由基对亚胺C=N键的插入串联环化策略,以2-氨基吡啶衍生物、芳基甲醛为原料、芳基溴乙炔为自由基源,在可见光促进和路易斯酸协同作用下,通过三组分串联反应,以70%~78%的产率实现了C3-芳甲基取代的咪唑并[1,2-a]吡啶衍生物的构建。目标产物结构经^(1)H NMR、^(13)C NMR和HR-MS确证。本方法无需额外添加光催化剂,操作简便、反应条件温和,具有较好的底物适用性和官能团耐受性,并且可以应用于唑吡坦的一步合成。

噻吩[3,2-b:4,5-b′]双苯并呋喃类化合物的合成及光物理性质研究

噻吩[3,2-b:4,5-b′]双苯并呋喃稠杂环化合物是一类重要的用于有机光电材料的并五苯的衍生物,该类稠杂环化合物的合成具有十分重要的意义。以廉价的2-碘苯甲醚、4-叔丁基-2-碘苯甲醚或2,4-二叔丁基-2-碘苯甲醚为原料,通过经典的Sonogashira偶联反应、脱保护基反应、Glaser-Hay偶联反应、碘亲电环化反应和噻吩合成反应五步反应成功合成了一类结构新颖的稠合杂环类化合物噻吩[3,2-b:4,5-b′]双苯并呋喃。关键的中间体双苯并呋喃二碘化合物(6a)和噻吩[3,2-b:4,5-b′]双苯并呋喃化合物(1a)均由单晶衍射分析确认了结构。该反应路线原料成本低,反应操作简单,总收率较高(1a:54%;1b:40%;1c:47%)。该合成策略为获得这类稠杂环化合物提供了一种有效的合成方法,所制备的化合物具有优异的光物理性质,有望用于光电材料领域。

钯催化环加成反应构建中环化合物的研究进展

中环化合物(7—11元环)广泛存在于许多天然产物及药物等功能分子之中,这些分子因具有优异的生物活性及特殊的骨架结构等优点,展现出极其重要的药用价值,如常见的抗癌药物紫杉醇、抗菌药物Spiroxin A等。同时,这类化合物也对化学、医药以及材料等诸多领域产生了深远的影响。但受动力学和热力学因素影响,中环化合物的高效构建依然是一个严峻的挑战。在科研工作者们的不懈努力下,近年来发展出多个新型环加成反应催化体系,其中钯催化环加成反应凭借高效、高选择性和原子经济性等优点在该领域得到了迅猛发展。本文详细介绍了近五年国内外有关钯催化环加成反应构建中环化合物研究的最新进展,旨在为该领域的发展提供一定的帮助。

光电联合催化烯烃自由基环合反应的研究进展

烯烃是重要的化工原料,可以制备药物、农药和涂料等高价值化学品。随着光催化和电催化氧化还原反应研究的发展,开发了将二者结合解决光/电各自局限性的光电联合催化技术。通过文献研究,根据3种不同自由基的产生方式,综述了光电联合催化烯烃自由基环合反应的研究进展。

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。

有机化学中的成环反应及其逆合成分析

为了深入理解有机化学中关键成环反应机制、优化反应条件及逆合成分析在合成路径设计中的应用,本研究采用了实验和理论相结合方法。以Diels-Alder反应、Mizoroki-Heck反应、环加成反应为例,分析了成环反应的实施步骤、产物的分离与纯化技术及产物结构鉴定技术。结果表明,精确控制实验条件可提高成环反应的产率,逆合成分析应用为合成路径优化提供了实践指导,研究发现为有机化学领域提供了新视角。

I_(2)介导的炔烃碘化环化反应的研究进展

通过催化炔烃环化的方式构建复杂分子的研究取得了重大进展,但这些构建方法仍受限于金属或Brønsted酸催化剂对炔烃的活化。分子碘具有类似过渡金属的活性,同时具有低毒性、高性价比、商业可得和易处理等优点,用分子碘活化炔烃环的异构化,从而简便、实用地构建碳环或杂环化合物,在有机合成中引起了相当大的关注。值得关注的是,分子碘具有良好的亲炔性,I_(2)介导的炔烃碘化环化反应已被证明是一种高效构建各种碘代杂环的有效方法。本文简述了I_(2)介导的炔烃碘化环化反应的一些研究进展。

超重力下二氯丙醇环化制备环氧氯丙烷新技术研究

对二氯丙醇环化反应制备环氧氯丙烷进行了理论研究,并将超重力强化反应技术应用于中试试验。利用超重力强化反应技术与环化塔耦合,通过加人氯化钙配制质量分数20%的氢氧化钙悬浊液,氯化钙质量分数达到20%时进行二氯丙醇环化反应。在该优化工艺条件下,环化塔氯化钙溶液中氯化钙质量分数最终达到26%左右,COD在10g/L以下,达到较理想的反应效果;另外,由于环化塔氯化钙浓度的提高,降低了装置蒸汽消耗,达到节能降耗目的。

Development of sterically hindered SPOs and enantioselective Ni-Al bimetallic catalyzed C-H cyclization of 4-oxoquinazolines with tethered alkenes

The Ni-Al bimetallic catalysis of intramolecular enantioselective and regioselective C-H cyclization of4-oxoquinazolines with tethered alkenes has been successfully developed.Some new secondary phosphine oxides(SPOs)with large steric hindrance(SPO6-11)were designed and successfully synthesized from readily available chiral amines or amino acids.The developed chiral SPOs as ligands or preligands demonstrate much higher efficiency in the asymmetric catalytic reactions than the reported traditional ones.A new class of chiral tricyclic pyrroloquinazolinones were obtained in up to 95%yield and 99%ee.