Rearrangement approaches to sesquiterpenes containing multiple contiguous quaternary carbon atoms. Total synthesis of (+/-)-myltayl-8(12)-ene and (+/-)-6-epijunicedranol

Details of the first total syntheses of the sesquiterpenes myltayl-8(12)-ene and 6-epijunicedran-8-ol are described. The aldehyde 13, obtained by Claisen rearrangement of cyclogeraniol, was transformed into the dienones 12 and 18. Boron trifluoride-diethyl ether mediated cyclization and rearrangement transformed the dienones 12 and 18 into the tricyclic ketones 16 and 17, efficiently creating three and four contiguous quaternary carbon atoms, respectively. Wittig methylenation of 16 furnished (+/-)-myltayl-8(12)-ene (11), whereas reduction of the ketone 17 furnished (+/-)-6-epijunicedranol (23).

Two regiospecific alternative strategies in the synthesis of (-)-valeranone

Two regiospecific modifications have been developed in the synthesis of valeranone. The first one is based on the regiospecific protection of a diol and the second is based on the Wittig reaction of a hemiacetal.

Synthesis of 2-Deoxy-2-C-alkyl Glycal and Glycopyranosides from 2-Hydroxy Glycal Ester

A method to convert 2-hydroxy glycol ester to the corresponding corresponding 2-deoxy-2-C-alkyl glycol in a facile manner, through key reactions including (i) C-allylation at C-1, (ii) Wittig reaction, and (iii) Cope rearrangement of a 1,5-diene derivative, is reported. The alpha-anomer of the 1,5-diene derivative underwent Cope rearrangement to afford 2-deoxy-2-C-glycal derivative, whereas the beta-anomer was found to be unreactive. Employing this sequence, was transformed to 3,4,6-tri-O-benzyl-2-deoxy-2-C-alkyl-1,5-anhydro-D-arabino-hex-1-enitol. 2-Deoxy-2-C-alkyl glycol derivative is a suitable glycosyl donor to prepare 2-deoxy-2-C-alkyl glycosides, mediated through haloglycosylation and a subsequent dehalogenation. A number of 2-deoxy-2-C-alkyl glycosides, with both glycosyl and nonglycosyl moieties at the reducing end, are thus prepared from the glycol.

Total synthesis and determination of the absolute configuration of 5,6-Dihydro-alpha-pyrone natural product synargentolide B

Enantiospecific total synthesis and determination of the absolute stereochemistry of the alpha-pyrone-containing natural product synargentolide B were accomplished. The absolute stereochemistry of the natural product was established by synthesizing the possible diastereomers and comparison of the data with those reported for the natural product. During the process, total synthesis of the putative structure of related natural product 6R-1S,2R,SR,6S-(tetraacetyloxy)-3E-heptenyl]-5,6-dihydro-2H-pyran-2-o ne was also accomplished and confirmed by X-ray crystal structure analysis. Wittig-Horner reaction of a chiral phosphonate derived from (S)-lactic acid and ring-closing metathesis were the key reactions during the course of the total synthesis.

Ring-opening metathesis of bulky norbornene monomers and the radical-mediated hydrophosphonation of olefins

This thesis discusses two major topics: the ring-opening metathesis polymerization (ROMP) of bulky monomers and the radical-mediated hydrophosphonation of olefins. The research into the ROMP of bulky monomers is further divided into three chapters: wedge-shaped monomers, the alternating copolymerization of 1-methyloxanorbornene derivatives with cyclooctene, and the kinetic resolution polymerization of 1-methyloxanorbornene derivatives. The wedge-shaped monomers can be polymerized into diblock copolymers that possess photonic crystal properties. The alternating copolymerization of 1-methyloxanorbornene derivatives with cyclooctene is performed with > 90% alternation via two different routes: typical alternating copolymerization and a sequence editing approach. The kinetic resolution polymerization of these same 1-methyloxanorbornene monomers achieves only modest selectivity (S=4), but there is evidence that the growing polymer chain forms a helix that influences the selectivity of the resolution. The last topic is the radical-mediated hydrophosphonation of olefins. This synthetic method provides access to Wittig reagents that are capable of highly cis-selective olefinations of aldehydes.

Synthesis and characterization of high-spin organic materials: prototypes for the polaronic ferromagnet

The design, synthesis and magnetic characterization of thiophene-based models for the polaronic ferromagnet are described. Synthetic strategies employing Wittig and Suzuki coupling were employed to produce polymers with extended π-systems. Oxidative doping using AsF_5 or I_2 produces radical cations (polarons) that are stable at room temperature. Magnetic characterization of the doped polymers, using SQUID-based magnetometry, indicates that in several instances ferromagnetic coupling of polarons occurs along the polymer chain. An investigation of the influence of polaron stability and delocalization on the magnitude of ferromagnetic coupling is pursued. A lower limit for mild, solution phase I_2 doping is established. A comparison of the variable temperature data of various polymers reveals that deleterious antiferromagnetic interactions are relatively insensitive to spin concentration, doping protocols or spin state. Comparison of the various polymers reveals useful design principles and suggests new directions for the development of magnetic organic materials. Novel strategies for solubilizing neutral polymeric materials in polar solvents are investigated.

The incorporation of stable bipyridinium spin-containing units into a polymeric high-spin array is explored. Preliminary results suggest that substituted diquat derivatives may serve as stable spin-containing units for the polaronic ferromagnet and are amenable to electrochemical doping. Synthetic efforts to prepare high-spin polymeric materials using viologens as a spin source have been unsuccessful.

端基官能化共轭齐聚物的设计与合成

和共轭聚合物相比，单分散共轭齐聚物具有结构确定、易提纯等优点，不仅是建立共轭体系结构与性能关系的最佳模型，而且是一类高纯度光电子材料，还是构造具有规整结构嵌段共聚物和超分子体系的理想构造单元。鉴于基于芴单元的共轭齐聚物与聚合物具有优异的光电性能，引入不同端基能够有效调节共轭齐聚物的性能，本论文以端基官能化齐聚芴为研究对象，设计与合成了具有不同端基结构的系列单分散齐聚芴，研究了它们基本的物理化学性质，主要成果与创新点如下： 1、利用Horner-Wadsworth-Emmons反应、Wittig反应和Heck偶联反应，交替引入极性、非极性反应端基，成功解决了发散法合成较长单分散共轭齐聚物过程中产物难以提纯的技术问题，合成了系列芴撑乙烯撑共轭齐聚物。其中，最长的齐聚物含11个芴单元，光谱外推得到的有效共轭长度可达19个重复单元。DSC和偏光显微镜研究表明，芴单元数大于5的齐聚物可形成向列型液晶相。含7个芴单元以上的齐聚物可用于制备有机发光二极管，含11个芴单元的齐聚物电致发光效率是相应聚合物的5倍。 2、通过Hagigara-Sonogashira偶联、Diels-Alder环加成等反应合成了一系列端基为刚性的苯乙炔基和五苯基苯的单分散齐聚芴。但典型Scholl反应条件不能实现完全氧化脱氢，获得六苯并晕苯封端的齐聚芴。光谱研究表明苯乙炔基的引入导致吸收光谱和荧光光谱有1-2 nm的红移。五苯基苯结构的引入能显著提高齐聚芴的Tg，从而提高齐聚物的形态稳定性。 3、利用Yamamoto反应，采用端基溴代的齐聚芴大分子单体聚合结合制备色谱分离，成功地制备了分子量超过20000 Da的单分散共轭聚合物，说明大分子单体聚合结合制备色谱分离制备单分散共轭聚合物是可行的。 4、通过Horner-Wadsworth-Emmons反应合成一系列端基为三苯胺乙烯撑的单分散齐聚芴，其中，最长的齐聚物含9个芴单元。光谱研究表明，随芴单元数的增加，两个三苯胺乙烯撑端基间共轭作用显著减弱，最大吸收波长蓝移；当芴的单元数≥3时，最大发射波长均位于450 nm，和聚芴和齐聚芴相比，这类共轭齐聚物的蓝光发光峰位更佳。电化学研究表明三苯胺乙烯撑单元的氧化还原过程不受齐聚芴单元长度的影响，该封端齐聚芴的HOMO能级主要是由三苯胺乙烯撑单元决定。 关键词：端基官能化，齐聚芴，单分散共轭聚合物

含电子传输基元发光聚合物的合成与表征

本论文是以提高聚合物电致发光器件发光效率和热稳定性为目的，从材料设计的角度出发，以具有电子传输性能和热稳定性1，3，4-噁二唑和1，2,4－三唑为构造单元，采用Wittig聚合反应合成了一系列含有1，3，4-噁二唑和1，2，4-三唑的发光聚合物，在载流子平衡和实现红、绿、蓝三基色发光方面取得了一些有益的结果，主要包括以下几点：1．合成了一系列含1，2，4-三唑单元和三芳胺单元的PPV型电致发光聚合物。研究了不同空穴传输单元对发光聚合物热性能和电化学性质的影响，结果表明，所有聚合物都具有比较高的玻璃化转变和热分解温度，其中由于联苯二胺中含有刚性联苯结构，使得含联苯二胺结构的聚合物较其它发光聚合物具有更高的玻璃化转变温度，并且由于联苯结构的空间位阻效应，减小了聚合物分子链间的相互作用，使得溶液态和薄膜态的光致发光峰位符合的很好。2.对所合成含1，2，4－三唑和三芳胺的发光聚合物进行了电致发光性能表征。研究了不同器件结构对发光亮度的影响。结果表明，所有的器件发光波长都在515－530nm之间。单层结构器件工TO/Polymer/Mg:Ag启动电压在6－9伏之间。发光亮度只有45 cd/m左右。双层结构工TO/Polymer/PBD/Mg:Ag发光亮度在100 cd/m~2左右，启动电压与单层器件几乎没有变化。这说明尽管在聚合物中引入了拉电子的三唑基团，但聚合物依然表现为空穴传输为主，这是由于三芳胺基团空穴迁移率比三唑的电子迁移率高；而且三芳胺单元和三唑基单元在聚合物中所占的比例也是三芳胺高的原因。3．我们首次合成了4－苯基－3，5－二（4一氯甲基苯基）－1，2，4－三唑化合物。中国科学院长春应用化学研究所博士论文经过反复实验最终确定了适合反应的合成路线，采用氯苯做溶剂，过氧化苯甲酞做引发剂，硫酞氯为反应试剂。合成的产物收率高，而且容易分离；采用三丁基磷盐为聚合单体，合成出高分子量的聚合物，并且聚合物基本上是以反式烯烃双键为主。4．以合成蓝色发光聚合物为目的。合成了二种1，2，4－三唑和联咔吟（咔哇）共聚的即V型蓝色发光聚合物和一种含有1，2，4－三唑的PPP型蓝色发光聚合物材料。研究结果表明，将1，2，4－三唑引入到电致发光聚合物中，有效地提高了聚合物的Tg，与相类似结构的蓝色发光聚合物相比，其热性能改善明显。聚合物的发光波长都在450pm左右，是比较纯正的蓝色发光。5．合成了有1,2,4一三唑(1,3，4一噁二唑）和不同MEH－PPV单元长度的发光聚合物，研究了不同的MEH－PPV单元长度对发光波长和玻璃化转变温度的影响。结果表明，当MEH－PPV单元长度增加时，发光波长和玻璃化转变温度都有向MEH－PPV接近的趋势。而且，由于聚合物中1，2，4－三唑中4位氮原子被苯环取代后提高了杂环的稳定性。在相同的MEH－PPV单元长度时，聚合物主链为1，2，4－三唑结构比聚合物主链是1，3，理一噁二唑的玻璃化转变温度高。6. 含1，2，4－三唑单元和三个单元长度MEH－PPV单元的发光聚合物的单层器件（ITO/Polymer/Mg：Ag）发光亮度为320cd/m~2。同MEH－PPV的单层EL器件相比，在相同的制备工艺条件下，聚合物的电致发光器佩件的发光亮度比MEH－PPV的单层电致发光器件高20％。7．研究表明1，3，4－噁二唑单元和1，2，4一三唑单元嵌入到MEH－PPV主链后，它们并不像脂肪柔性链那样完全中断了聚合物共扼性的延伸，1，3，4一噁二唑单元和1，2，4一三唑单元依然是聚合物的共扼成分，只是中国科学院长春应用化学研究所博士论文降低了聚合物的有效共辘程度；并且由于1，2，4一三唑单元空间结构特性使得聚合物有效共扼程度比1，3，4一噁二唑单元降低的更多。8.合成了含有1，3，4一噁二唑单元和不同发光中心的小分子发光材料，我们发现带烷氧基取代的发光小分子发光颜色向长波方向移动。而带有联苯结构的发光小分子发光颜色向短波长方向移动。9．发光小分子的紫外吸收峰与1，3，4－噁二唑单元的发光峰位存在着非常大的重叠，当用1，3，4－噁二唑的紫外最大吸收波长激发发光材料时，1，3，4－噁二唑所发出的光能够被共扼的发光小分子吸收，存在着能量转移的现象。

含空穴传输基团PPV的合成与性能研究

该论文以提高聚苯撑乙烯（PPV）类发光聚合物的空穴传输性能为主要目的,通过将具有较高空穴传输能力的芳胺类小分子基元引入发光聚合物分子链,设计并合成了一系列含芳胺基元的PPV聚合物.另外,还通过对分子结构进行设计和控制,获得了红绿蓝三基色发光.最后还利用在共轭分子主链上引入具有三维空间位阻的侧链基团,获得了高效率的绿色发光聚合物材料.

PPV齐聚物为基元的发光材料的合成与性能研究

PPV齐聚物（OPV）因为具有确定的发光结构，高的发光效率，和光电活性，被广泛的关注。本论文本围绕PPV齐聚物（OPV）展开研究。设计合成了有机／无机杂化型和热交联型高分子发光材料，解决了制作多层器件过程中，旋涂时下面的薄膜容易被溶解的问题。我们设计合成了一系列能量转移和传输平衡型高分子发光材料，并对材料进行了优化。1、利用末端带活性双酚的OPV与二甲基二苯胺基硅烷通过熔融缩聚反应，合成出以硅氧烷为嵌段单元的发光聚合物，并通过调节OPV单体上的取代基团实现聚合物的蓝光发射。2、在PPV的末端引入可交联的苯乙烯基元，在高温下实现PPV的交联，得到了耐溶剂的PPV薄膜，利用其耐溶剂的特点用简单的旋涂的方法制备了双层器件，与单层器件相比效率提高了约13倍，器件的最大亮度达7O0cd／m2。3、通过化学修饰在OPV的两端引入了活性的三乙氧基硅烷，利用三乙氧基硅的反应活性，将OPV通过Sol-Gd的方法固定到SiO2的基质中，OPV与基质之间的作用为化学键，这样有效的减少了OPV在基质中的聚集。同时我们制备了PMMA与OPV通过物理共混得到的Si-OPV/PMMA薄膜和不带活性基团的Me-OPV，通过Sol-Gel制备了Me-OPV／SiO2薄膜，结果表明，采用物理掺杂时，客体OPV在主体中存在明显的聚集；经过热处理后只有化学掺杂的薄膜形态和光谱仍然保持稳定。4、将两种不同的OPV发光单元通过稳定的芳醚键连接，得到了热稳性的聚合物，由于不同的发光单元之间的吸收和发射光谱存在重叠，我们观察到分子内的能量转移现象，通过能量转移提高了聚合物在薄膜和溶液下的量子效率和相应的电致发光效率。5、为了改善PPV类能量转移型发光分子的传输特性，通过Wittig反应在聚合物主链中引入了电子传输单元：噁二唑，三唑。为了优化材料我们调节了传输单元在主链中的含量，通过器件数据优化出电子传输基元在主链中的最佳含量。使得优化后的材料的器件效率比未引入传输单元的提高了10倍以上，最大亮度达到1300cd／m2。

传输型电致发光聚合物的合成与表征

高分子发光材料除应具有优良发光性能外，还需具有优良电子传输性能和空穴传输性能。本论文以此为出发点，将具有优良空穴传输性能的芳胺类化合物和具有优良电子传输性能的噁二唑类化合物，通过无规共聚合调控发光基元和两类传输基元的含量，合成了系列的传输与发光一体化的即V类高分子发光材料，并探讨了聚合物本身的基本特性。同时，设计和制备了相应的单层结构器件和掺杂器件，考察了器件的器件性能。本论文主要工作内容及结果如下：1、成功的利用三类王芳胺类双醛：4，4'-二醛基-（4-辛氧基-苯基）-二苯胺（TPA双醛）、N，N'-二（4-辛氧基一苯基）-N，N'-二（4-甲醛基-苯基）-1，4-苯二胺（PDA双醛）和N，N，-二（4-辛氧基-苯基）-N，N，-二（4-甲醛基-苯基）-4，4' 联苯二胺（TPD双醛）和wittig麟盐无规共聚，得到三个系列双极传输高分子发光材料。2、聚合物主链中同时引入三芳胺类空穴传输基团和噁二唑电子传输基团，提高了器件性能。在TPA系列中，同时含有三芳胺和噁二唑全基团的聚合物比仅含有三芳胺基团聚合物的单层器件亮度及效率分别提高29和22倍，同时使器件的启动电压从9.3V下降到2．7V。在同样比较的情况下，在PDA系列中，聚合物的器件亮度及效率要提高近8倍，同时使器件的启动电压从5.3V下降到4.5V。在TPD系列中，聚合物的器件亮度及效率要提高44和38倍，同时使器件的启动电压从7.5V下降到5.7V。3、含有噁二唑基团聚合物分子的这种D-A体系所具有的分子内电荷转移性质，导致其荧光光谱和电致发光光谱红移。其中，TPA系列和TPD系列的电致发光光谱从绿光红移到了黄绿光，而PDA系列聚合物的电致发光光谱从黄绿光红移到了橙光。4、刚性的噁二唑基团的引入提高了聚合物的热稳定性，T以系列聚合物、PDA系列聚合物和TPD系列聚合物中含有噁二唑基团的聚合物的玻璃化转变温度在112-229℃之间，其热分解温度超过420℃。5、此三个系列聚合物中同时含有空穴和电子传输基元的双极分子溶液的紫外一可见吸收光谱和荧光光谱都有明显的溶剂化效应，表现出较强的分子内电荷转移特性。6、利用TPA系列聚合物中性能最好的聚合物TPA-OXD-PV1的良好电子和空穴传输性质，构造的单层掺杂器件，实现了橙色和红色发光。

Synthesis, characterization, and electroluminescence of PPV copolymers containing electron and hole-transporting units

Three series of poly(phenylene vinylene) (PPV) derivatives containing hole-transporting triphenylamine derivatives [N-(4-octoxylphenyl)diphenylamine, N,N'-di(4-octyloxylphenyl)-N,N'-diphenyl-1,4-phenylenediamine, and N,N'-di(4-octoxylphenyl)-N,N'-diphenylbenzidine] (donor) and electron-transporting oxadiazole unit (2,5-diphenyl-1,3,4-oxadiazole) (acceptor) in the main chain were synthesized by improved Wittig copolymerization. The resulting donor-acceptor (D-A) polymers are readily soluble in common organic solvents, such as chloroform, dichloroethane, THF, and toluene.

Crosslinkable poly (p-phenylenevinylene) derivative

To simplify the fabrication of multilayer light-emitting diodes, we prepared a p-phenylenevinylene-based polymer capped with crosslinkable styrene through a Wittig reaction. Insoluble poly(p-phenylenevinylene) derivative (PPVD) films were prepared by a thermal treatment. The photoluminescence and ultraviolet-visible (UV-vis) absorbance of crosslinked films and noncrosslinked films were studied. We also studied the solvent resistance of crosslinked PPV films with UV-vis absorption spectra and atomic force microscopy. Double-layer devices using crosslinked PPVD as an emitting layer, 2-(4-tert-butylphenyl)-5-phenyl-1,3,4-oxadiazole (PBD) in poly(methyl methacrylate) as an electron-transporting layer, and calcium as a cathode were fabricated. A maximum luminance efficiency of 0.70 cd/A and a maximum brightness of 740 cd/m(2) at 16 V were demonstrated. A 12-fold improvement in the luminance efficiency with respect to that of single-layer devices was realized.

Novel soluble N-phenyl-carbazole-containing PPVs for light-emitting devices: Synthesis, electrochemical, optical, and electroluminescent properties

Novel PPV derivatives (PCA8-PV and PCA8-MEHPV) containing N-phenyl-carbazole units on the back-bone were successfully synthesized by the Wittig polycondensation of 3,6-bisformyl-N-(4-octyloxy-phenyl)carbazole with the corresponding tributyl phosphonium salts in good yields. The newly formed and dominant trans vinylene double bonds were confirmed by FT-IR and NMR spectroscopy. The polymers (with (M) over bar (w) of 6289 for PCA8-PV and 7387 for PCA8-MEHPV) were soluble in common organic solvents and displayed high thermal stability (T(g)s are 110.7 degreesC for PCA8-PV and 92.2 degreesC for PCA8-MEHPV, respectively) because of the incorporation of the N-phenyl-carbazole units. Cyclic voltammetry investigations (onsets: 0.8 V for PCA8-PV and 0.7 V for PCA8-MEHPV) suggested that the polymers possess enhanced hole injection/transport properties, which can be also attributed to the N-phenyl-carbazole units on the backbone. Both the single-layer and the double-layer light-emitting diodes (LEDs) that used the polymers as the active layer emitted a greenish-blue or bluish-green light (the maximum emissions located 494 nm for PCA8-PV and 507 nm for PCA8-MEHPV, respectively).

Phenylene vinylene-based electroluminescent polymers with electron transport block in the main chain

We report a new route for the design of soluble phenylene vinylene (PV) based electroluminescent polymers bearing electron-deficient oxadizole (OXD) and triazole (TZ) moieties in the main chains with the aryloxy linkage. Both series of the PV-based polymers were prepared by Wittig reaction. By properly adjusting the OXD and/or TZ content through copolymerization, we can achieve an enhanced balance of hole- and electron injections, such that the device efficiency is significantly improved. Light-emitting diodes fabricated from P1, P2, P3, P4, P5, P6, and P7 with the configuration of Indium-Tin Oxide (ITO)/Poly (styrene sulfonic acid) doped poly (ethylenedioxythiophene) (PEDOT)/polymer/Ca/Al, emit bright green light with the maximum peak around 500 nm. For the device using the optimal polymer (P4) as emitting layer, a maximum brightness of 1300 cd/m(2) at 20 V and a maximum luminance efficiency of 0.325 cd/A can be obtained.