（±）－耳壳藻内酯全合成研究（Ⅰ）

从柠檬醛出发，经环化、氰基化、烯丙位氧化、水解及环化还原等５步反应，合成了（±）－耳壳藻内酯（１）。     

（±）—耳壳藻内脂全合成研究（I）

从柠檬醛出发，经环化，氰基化，烯丙位氧化，水解及环化还原等５步反应，合成了（±）－耳壳藻内酯（１）。     

由炔的金属烯丙化合成二烯烃和环烯烃

炔的金属烯丙化(allylmetallation)是炔的金属烃化反应(carbometallation)的一种,是立体专一地合成多取代烯烃的有效途径。铝烯丙化(allylalumination)和锌烯丙化(allyl-     

新的手性联吡啶配体立体选择催化环丙烷化

近年来,手性联吡啶已广泛应用于不对称均相催化,如不对称环丙烷化[1]、烯丙位氧化[1]、烯丙位取代[2]及有机锌加成醛[3]等反应.     

毛细管流动色谱法研究丙烯在HZSM-5上的聚合作用

用毛细管流动色谱法分析丙烯在HZSM-5上聚合反应尾气,将此法与气相色谱-质谱联用技术相结合,对各反应产物分别定性,此法即可一次完成丙烯聚合反应产物的完全分离和定量。随着反应温度升高,尾气中芳构化产物增加,C_(4-6)链烃含量下降;丙烯通过齐聚物环化脱氢进行芳构化。     

含茂基稀土金属有机络合物催化剂在有机合成中的应用

综述了含茂基稀土金属有机络合物催化下的不饱和烃（或其取取衍生物）转化反应及其在有机合成中的作用。重点阐述了含茂基稀土金属有机络合物催化的烯烃氧化，氢化环化；烯烃和炔烃的氢化硅化，1，5－或1，6－二烯或烯炔的氢化硅化／环化，氨基取代烯烃，炔烃，丙二烯等的氢化胺化／环化等反应在有机合成中的主要用途，这些反应在形成碳－杂原子键，碳－碳键，碳环和杂环等方面具有广泛的应用前景。讨论了这些反应的催化循环机制，区域稳定性，对映选择性，非对映选择性及其影响因素。     

烯丙位氧化的几种方法

综述了近年来烯丙位氧化的研究进展，详细讨论了过渡金属及其络合物、硒化 合物在烯丙位氧化中的应用，并简述了丁基锂方法、固相催化方法、生物氧化方法 和次氯酸钠氧化方法在烯丙位氧化中的应用．     

钯催化的烯丙位C—H键官能团化:新催化体系的发展

烯丙位碳氢键活化官能化反应是构建碳碳键、碳杂原子键最直接的方法,也是最近有机化学研究的热点之一.从烯丙基底物类型和亲核试剂类型的角度出发,总结了最近几年来钯催化的烯丙位碳氢键活化官能团化反应及其在不对称合成中应用的最新研究进展.同时分析了各种新的钯催化体系在底物兼容性和亲核试剂范围上的优势和不足,并对今后烯丙位碳氢键活化的发展进行了展望.     

Fe(0)催化三氯乙酸烯丙酯的环化反应研究

通过对Fe(O)催化烯烃自由基环化反应的研究，发现以Fe(O)为催化剂催化三氯 乙酸烯丙酯分子内自由基环化反应可以高化学选择性得到五元环内酯产物，反应中 不需加入配体。和大多数自由基反应一样，反应温度与催化剂用量对该反应的转化 率和产率有着很大的影响。     

铜试剂介导下烯胺酮的氧化环化/迁移合成取代的2H-氮杂丙烯啶的方法

报道了铜试剂介导下烯胺酮化合物通过氧化环化/迁移反应合成2-苯酰氧基-2H-氮杂丙烯啶的新方法.该方法具有反应条件温和、反应时间短和操作简单等优点.     

Aromaticity and Pericyclic Reactions

Pericyclic reactions formally resemble the conversion of one Kekulé structure into another; the transition state may be “aromatic”, “nonaromatic”, or “antiaromatic”. Thermally induced pericyclic reactions proceed preferentially via aromatic transition states whereas their photochemical counterparts lead to products that are formed via antiaromatic transition states.     

氯代酸气相热消除反应的理论研究

应用半经验分子轨道ＡＭ１法，辅以Ｂｅｒｎｙ梯度优化法对３－氯丙酸和２－氯丁酸在气相中的热消除反应进行了理论研究。计算结果表明：（１）３－氯丙酸在气相中的热消除反应可以通过六元环过渡态机理和四元环过渡态机平行进行得到产物；（２）２－氯丁酸的热消除则可以通过五元环过渡态机理和四元环过渡态机理平行进行；（３）对３－氯丙酸的热消除反应，以了环过渡态进行反应的活化势垒较低，而２－氯丁酸的热消除反应则是五元环     

β-羟基丙醛基态与激发态氢迁移反应的从头算研究

本文用从头算RHF和UHF方法在3-21G基组上研究了β-羟基丙醛基态和激发态分解为甲醛和乙烯醇的反应机理。优化得到了各反应途径的过渡态和中间体, 其结果为: 基态β-羟基丙醛经过一个六元环过渡态和一个氢键中间体形成产物, 反应属于氢迁移和断键的协同过程; 激发三态β-羟基丙醛的分解途径首先经过一个氢迁移六元环过渡态形成双自由基中间体, 然后该中间体的分解包括两条相互竞争的途径, 它们各自经过一个断碳碳键的过渡态和一个氢键激-基态配合物中间体而形成两类产物, 一类为甲醛的基态和乙烯醇的激发态, 另一类为甲醛的激发态和乙烯醇的基态。激发态反应的两条通道均属于先氢迁移后断键分解的分步过程, 且反应的第二步为速控步骤。计算结果表明, 激发态反应活化位垒都比基态的低。     

Long-range intramolecular S → N acyl migration: a study of the formation of native peptide analogues via 13-, 15-, and 16-membered cyclic transition states

The intramolecular long-range S → N acyl migration via 13-, 15-, and 16-membered cyclic transition states to form native tetra- and pentapeptide analogues was studied on S-acylcysteine peptides containing β- or γ-amino acids. The pH-dependency study of the acyl migration via a 15-membered cyclic transition state indicated that the reaction is favored at a pH range from 7.0 to 7.6. Experimental observations are supported by structural and computational investigations.     

Facile preparation of transition metal nanoparticles stabilized by well-defined (co)polymers synthesized via aqueous reversible addition-fragmentation chain transfer polymerization

Herein we disclose a facile method for the preparation of (co)polymer-stabilized transition metal colloids, via the "grafting-to" approach. The method takes advantage of the fact that (co)polymers synthesized in aqueous media, in a controlled fashion, via reversible addition-fragmentation chain transfer bear thiocarbonylthio end groups. These are readily reduced to yield (co)polymers with thiol end groups. When the reduction is performed, with NaBH(4), for example, in aqueous media in the presence of an appropriate transition metal species, (co)polymer-stabilized metal nanoparticles are formed in which the size and size distribution are dependent upon the individual transition metals. Colloid formation is confirmed by transmission electron microscopy and UV-vis spectroscopy.     

An MO study of regioselective amine addition to ortho-quinones relevant to melanogenesis

Energy profiles for alternative intramolecular cyclisations of 4-(aminoalkyl)-ortho-quinones have been calculated using the AM1 method and ab initio energies of the transition states are determined. In all the cases cyclisation at position 5 occurs via a significantly lower energy transition state than cyclisation at position 3. This is consistent with experimental observations. Optimal trajectories for attack have been determined from a study of the reactions of methylamine with 4-methyl-ortho-quinone. For cyclisation of aminoalkyl derivatives deviation from the optimal direction is less for reaction at position 5 but constraint on angle of attack only partially accounts for the regioselectivity. Intrinsic differences in the electronic energies of the alternative transition states are the main contributor to regioselectivity. The relative energies of transition states can be modified by variation of the substituent at position 4. The calculations suggest that seven-membered ring formation may occur via a boat transition state and steric hindrance in the seven-membered transition states may account for the experimentally observed influence of N-substituents on the mode of reaction.     

SiH3与NO2反应机理的理论研究

The reaction between silyl radicals and nitric oxide was studied by using the B3LYP/6 311G and the high-level electron-correlation CCSD(T)/6-311G methods. The geometries for reactants, the transition states and the products were completely optimized. All the transition states are verified by the vibrational analysis and the intrinsic reaction coordinate (IRC) calculations. The results show that the reaction is via multi-channel and multi-step. Five products may be formed via the complex reaction channels, i.e. association, H-shift and dissociation.     

Reactions of phosphate and phosphorothiolate diesters with nucleophiles: comparison of transition state structures

A series of methyl aryl phosphorothiolate esters (SP) were synthesized and their reactions with pyridine derivatives were compared to those for methyl aryl phosphate esters (OP). Results show that SP esters react with pyridine nucleophiles via a concerted S(N)2(P) mechanism. Br?nsted analysis suggests that reactions of both SP and OP esters proceed via transition states with dissociative character. The overall similarity of the transition state structures supports the use of phosphorothiolates as substrate analogues to probe mechanisms of enzyme-catalyzed phosphoryl transfer reactions.     

Ab initio study of the unimolecular pyrolysis mechanisms of monothioformic acid

The mechanisms of the possible unimolecular reactions occurring during the pyrolysis of the four tautomers (two conformers of thiol- and two conformers of thiono-) of monothioformic acid have been proposed and investigated by ab initio methods with STO-3G and 6-31G⁷ basis sets. The effects of valence electron correlation were included by Møller-Plesset (MP) perturbation theory to the fourth order at the 6-31G⁷ level. Our best results of the activation energies are given by MP4/6-31G⁷//HF/ 6-31G⁷ plus scaled zero-point energy. The barrier heights of the dehydrogenation (via a four-centre transition state) and dehydrogensuphidation (via a three-centre transition state) of thiolformic acid pyrolysis are 67.47 and 67.09 kcal mol⁻¹ respectively. The s-cis thionformic acid is dehydrated via a three-centre transition state. The activation energy of the process (81.18 kcal mol⁻¹) is much higher than the activation energy of the dehydrogenation of the s-trans form (68.83 kcal mol⁻¹) which is dehydrogenated via a four-centre transition state. These results suggest that in thionformic acid pyrolysis, the dehyrogenation of the s-cis form is more favourable than the dehydration of the s-trans form.     

Experimental evidence for chair-like transition states in aldol reactions of methyl ketone lithium enolates: stereoselective synthesis and utilization of a deuterium-labeled enolate as a probe of reaction stereochemistry

Aldol reactions of methyl ketone lithium enolates proceed via chairlike Zimmerman-Traxler transition states with 7:1 to 50:1 preference over alternative, boatlike transition structures, as determined by studies involving the configurationally stable deuterium-labeled enol silane 18 as the lithium enolate precursor.