DDQ/TBN催化分子氧氧化芳构化合成罗素伐他汀母核中间体

以DDQ和TBN为催化剂,氧气为氧源,研究了罗素伐他汀母核合成过程中从多取代二氢嘧啶(I)转化为相应的嘧啶中间体(II)的氧化芳构化反应.考察了反应温度,反应溶剂及催化剂用量对氧化芳构化反应的影响.优化实验结果表明,以2%的DDQ及10%TBN为催化剂,氧气为氧源,在甲苯中60℃反应24 h,多取代二氢嘧啶完全转化,获得高选择性的氧化芳构化产物嘧啶中间体(II).在50 mmol规模的氧化芳构化反应的实验中获得了98.8%的分离收率,反应的后处理方便简洁.     

Metal-Free Highly Efficient Aerobic Oxidation of Sulfides to Sulfoxides Catalyzed by DBDMH/TBN/H2O

A highly efficient metal-free catalytic system, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH)–tert-butylnitrite (TBN)–H₂O, has been developed for an environmentally friendly and economical aerobic acid-free oxidation of sulfides. TBN was identified as an efficient NO equivalent for the activation of molecular oxygen. Under optimal conditions, a variety of sulfides substrates were converted into their corresponding sulfoxides in good yields by molecular oxygen.     

DDQ/TFA： an Efficient Nonmetallic Reagent System for the Oxidative Coupling to Construct Phenanthrene Rings

A mild synthetic method of a series of phenanthrenes with different substituents on the phenanthrene ring is described.The method involves intramolecular oxidative coupling with 2,3-dichloro-5,6-dicyanobenzoquinone （DDQ）/trifluoroacetic acid（TFA） as oxidant to produce phenanthrenes in high yields and is fit for large-scale preparation.Furthermore,DDQ can be regenerated by a simple oxidation.The present approach solves a key step for the synthesis of polycyclic structures related to an alkaloid tylophorine.     

多取代芳香族化合物的合成 5.卤素-苯硒基取代的丁二烯和丁炔二酸二甲酯的环加成-芳构化串连反应

本文报道用环加成－芳构化串连反应制备多取代芳香族化合物的方法。将１－氯－２－卤－３－苯硒基－１，３－丁二烯（５）与丁炔二酸二甲酯进行Ｄｉｅｌｓ－Ａｌｄｅｒ反应时，能直接生成多取代的芳香族化合物４－苯硒基－５－卤代邻苯二甲酸二甲酯（４）。若用２－卤素－３－苯硒基－１，３－丁二烯（１）与丁炔二酸二甲酯进行Ｄｉｅｌｓ－Ａｌｄｅｒ反应，只得到正常的加成产物４－苯硒基－５－卤素－１，４－环己二烯－１，２－二甲酸二甲酯（３），需再用ＤＤＱ处理，才得到多取代芳香族化合物（４）。     

Copper‐Catalyzed NH Insertion and Oxidative Aromatization Cascade: Facile Synthesis of 2‐Arylaminophenols

A copper‐catalyzed cascade reaction of N‐H insertion and oxidative aromatization has been developed. 2‐Arylaminophenols have been prepared in moderate to high yields from the diazo substrates. Moreover, this newly established methodology allows efficient access to natural 1‐oxygenated carbazole alkaloids, such as glycozolicine and murrayafoline A.     

KF/Al2O3催化下吡啶并[2,3-d]嘧啶衍生物的三组分一步合成

以芳醛、丙二腈和2,6-二羟基-4-氨基嘧啶为原料, 在KF/Al₂O₃催化下以乙醇为溶剂, 在80 ℃三组分一步合成了一系列吡啶并[2,3-d]嘧啶衍生物, 有趣的是在空气氧化作用下进一步发生了芳构化作用. 和其它合成方法相比, 该方法具有反应条件温和、容易操作和产率较高等优点, 并通过IR, ¹H NMR和元素分析确证产物的结构.     

Study of the Transient Reactive Pd(IV) Intermediate in the Pd(OAc)2‐Catalyzed Oxidative Coupling Reaction System by Electrospray Ionization Tandem Mass Spectrometry

Pd‐catalyzed oxidative coupling reaction was of great importance in the aromatic C? H activation and the formation of new C? O and C? C bonds. Sanford has pioneered practical, directed C? H activation reactions employing Pd(OAc)₂ as catalyst since 2004. However, until now, the speculated reactive Pd(IV) transient intermediates in these reactions have not been isolated or directly detected from reaction solution. Electrospray ionization tandem mass spectrometry (ESI‐MS/MS) was used to intercept and characterize the reactive Pd(IV) transient intermediates in the solutions of Pd(OAc)₂‐catalyzed oxidative coupling reactions. In this study, the Pd(IV) transient intermediates were detected from the solution of Pd(OAc)₂‐catalyzed oxidative coupling reactions by ESI‐MS and the MS/MS of the intercepted Pd(IV) transient intermediate in reaction system was the same with the synthesized authentic Pd(IV) complex. Our ESI‐MS(/MS) studies confirmed the presence of Pd(IV) reaction transient intermediates. Most interestingly, the MS/MS of Pd(IV) transient intermediates showed the reductive elimination reactivity to Pd(II) complexes with new C? O bond formation into product in gas phase, which was consistent with the proposed reactivity of the Pd(IV) transient intermediates in solution.     

Copper/Palladium‐Cocatalyzed Aerobic Synthesis of Bisaryl Ketones from Olefins via C‐C Double Bonds Cleavage

A novel palladium/copper‐catalyzed aerobic synthesis of bisaryl ketones from 1,2‐diarylalkenes via C‐C double bonds cleavage has been described. This reaction constitutes a new transformation from 1,2‐diarylalkenes into bisaryl ketones, providing a unifying, simple and environmentally friendly complement to the available methods.     

芳构化法合成2,5-二羟基对苯二甲酸反应机理的密度泛函理论研究

采用密度泛函理论（DFT）计算,研究了由1,4-环己二酮-2,5-二甲酸二甲酯（DMSS）制备2,5-二羟基对苯二甲酸（DHTA）的反应机理。其中,采用IEFPCM溶剂模型着重计算了DMSS由酮式互变异构为烯醇式的溶剂效应,并探究了碘在催化DMSS烯醇式氧化芳构化过程中的作用机制。计算结果表明,在溶剂分子的辅助下,DMSS酮-烯醇式互变异构反应的能垒显著降低;芳构化过程中,碘首先与过氧化氢反应生成活性物质次碘酸,其催化DMSS烯醇式发生碘代反应,并经过后续的消去和互变异构生成2,5-二羟基对苯二甲酸二甲酯（DMDHT）,DMDHT进一步水解生成DHTA。同时,通过核磁共振氢谱测试验证了DMSS酮-烯醇式互变异构的溶剂效应;反应性能考评实验结果表明,相较于无催化剂,在碘的催化作用下,DMDHT产品的纯度和收率更高。     

铜离子的引入对甲烷无氧芳构化催化剂Mo/CuH-ZSM-5中Mo物种化学状态的影响

对比考察了Mo/CuH-ZSM-5和Mo/H-ZSM-5催化剂的甲烷无氧芳构化性能,并用XRD,XPS,ESR等多种测试手段对反应前后催化剂上的Mo物种及铜助剂的价态变化进行了详细研究,发现Cu(Ⅱ)部分取代H-ZSM-5交换位上的H⁺后,抑制了活性组分MoO₃的还原,而Cu物种自身被还原,进而将这种价态变化与催化剂的活性进行了关联.     

添加Fe对Pt/KL沸石芳构化及抗硫性能的影响

Pt／KL沸五催化剂对正己烷的芳构化反应具有特别高的活性和选择性，但是它对原料中硫的存在非常敏感，要求合硫量小平川’，而工业催化剂的硫含量允许10’．这使得Pt／KL佛石催化剂一直未能工业化山．近年来，文献上开始出现了一些KL佛石上负载双金属的研究工作［’－’1．通过     

Diels–Alder/Oxidative Aromatization Approach towards the All‐Carbon DEF Tricyclic Skeleton of Daphenylline

Daphenylline is a recently isolated Daphniphyllum alkaloid with an unprecedented novel hexacyclic scaffold. In this study, the synthesis of the fused all‐carbon DEF tricyclic skeleton of daphenylline has been accomplished. Key steps of the reported sequence involve Evans asymmetric allylation, aldol condensation, Diels–Alder reaction, and oxidative aromatization reactions. The developed strategy might lead to the total synthesis of daphenylline.     

Study on the Total Synthesis of Ecteinascidin 743 and Its Analogues-Construction of A Pentacyclic Intermediate

A concise and efficient synthesis of the pentacyclic intermediate 1,as a simple model compound of Ecteinascidin 743 and its analogues,is described.     

CuCl/菲咯啉/甲基咪唑催化甲醇/乙醇氧化羰化一步合成碳酸甲乙酯

 研究了CuCl与含氮杂环化合物配体1, 10-菲咯啉(phen)和N-甲基咪唑(NMI)形成的配合物催化剂对甲醇/乙醇氧化羰化一步合成碳酸甲乙酯(MEC)反应的催化活性. 讨论了配体的配比、甲醇和乙醇的相对用量、温度及压力等因素对甲醇和乙醇的转化率及MEC产率的影响. 结果表明,CuCl/phen/NMI原位配合物催化剂对氧化羰化一步合成MEC反应具有较高的催化活性. 配体phen及NMI对反应产物的选择性有明显的调变作用,甲醇和乙醇的配比对产物分布有很大的影响. 在V(MeOH)/V(EtOH)=0.25,c(CuCl)=0.20 mol/L,n(CuCl)∶n(NMI)∶n(phen)=1∶1.25∶1.25,p=2.40 MPa,θ=120 ℃的条件下反应2 h,甲醇的转化率为44.3%,乙醇的转化率为22.3%,MEC的产率为10.4%.     

常山酮中间体的合成工艺改进

以2-乙酰呋喃为起始原料,经扩环、甲基化、去质子化、亲核加成、缩酮化、Rh/C催化氢化及水解等反应合成了常山酮中间体--1-(3-甲氧基哌啶-2-基)丙酮,总收率40.2%,其结构经¹H NMR和ESI-MS确证。     

Nickel‐Catalyzed Oxidative C−H/N−H Isocyanide Insertion: An Efficient Synthesis of Iminoisoindolinone Derivatives

Transition metal‐catalyzed isocyanide insertion has served as a fundamental and important chemical transformation. Classical isocyanide insertion usually occurs between organohalides and nucleophiles, which normally involves tedious and non‐atom‐economical prefunctionalization processes. However, oxidative C?H/N?H isocyanide insertion offers an efficient and green alternative. Herein, a nickel‐catayzed oxidative C?H/N?H isocyanide insertion of aminoquinoline benzamides has been developed. Different kinds of iminoisoindolinone derivatives could be synthesized in good yields by utilizing Ni(acac)₂ as the catalyst. In this transformation, isocyanide serves as an efficient C1 connector, which further inserted into two simple nucleophiles (C?H/N?H), representing an effective way to construct heterocycles.     

在透氧膜反应器中进行甲烷氧化偶联反应的研究

 混合导体透氧膜是一类同时具有电子和氧离子两类导电性的陶瓷膜．在高温下，氧会以氧离子的形式透过透氧膜，因此在膜表面存在丰富的氧物种（O－，O－2，O2－2和O2－），这些氧物种能够提高甲烷氧化偶联（OCM）反应的C2选择性．采用挤压的方法制备出致密的Ba0．5Sr0．5Co0．8Fe0．2O3－δ（BSCFO）透氧膜管，并考察了此透氧膜管对OCM反应的催化性能．发现BSCFO的C2生成速率比La0．6Sr0．4Co0．8Fe0．2O3－δ（LSCFO）和La－Ba－Co－Fe－O（LBCFO）要高得多，其原因主要是由于BSCFO中的氧空缺浓度比较高．高的氧空缺浓度不仅能够加速氧离子的传输，而且能够提高甲烷分子的活化速度，所以BSCFO具有比LSCFO和LBCFO更好的催化性能．C2生成速率随着反应温度及原料气中甲烷浓度的升高而升高，C2选择性取决于氧离子结合与OCM反应竞争的结果，高的氧离子结合速率会降低C2选择性．甲烷转化率随着富氧侧氧分压的升高而升高，但C2选择性则随着氧分压的升高而降低．这说\r\n明在OCM过程中气相反应起着重要的作用．     

Rhodium-Catalyzed Oxidative Annulation of 2- or 7-Arylindoles with Alkenes/Alkynes Using Molecular Oxygen as the Sole Oxidant Enabled by Quaternary Ammonium Salt

Developing an efficient catalytic system using molecular oxygen as the oxidant for rhodium-catalyzed cross-dehydrogenative coupling remains highly desirable. Herein, rhodium-catalyzed oxidative annulation of 2- or 7-phenyl-1H-indoles with alkenes or alkynes to assemble valuable 6H-isoindolo[2,1-a]indoles, pyrrolo[3,2,1-de]phenanthridines, or indolo[2,1-a]isoquinolines using the atmospheric pressure of air as the sole oxidant enabled by quaternary ammonium salt has been accomplished. Mechanistic studies provided evidence for the fast intramolecular aza-Michael reaction and aerobic reoxidation of Rh(I)/Rh(III), facilitated by the addition of quaternary ammonium salt.     

Unexpectedly Simple Synthesis of Benzazoles by tBuONa‐Catalyzed Direct Aerobic Oxidative Cyclocondensation of o‐Thio/Hydroxy/Aminoanilines with Alcohols under Air

tBuONa‐catalyzed direct aerobic oxidative cyclocondensation reactions of readily available alcohols and o‐thio/hydroxy/aminoanilines under air have been developed and provide an efficient, practical, and green method for the synthesis of benzazoles. Mechanistic studies revealed that o‐substituted anilines promote the initial aerobic alcohol‐oxidation step, which explains the high reactivity and success of this unexpectedly simple and practical cyclocondensation method.