The reduction ring-opening reaction of imidazoline

A new reduction ring-opening reaction of 2-imidazoline with sodium borohydride is reported, and the effect of reaction condition on the yield, reaction mechanism and the use of the new reaction in synthesis of ethylenediamine derivatives are discussed. A new method for the preparation of unsymmetrical substituted ethylenediamine via the reduction ring-opening reaction of imidazoline is provided.     

基本化学反应形式的系统分类

The old classification of basic chemical reactions was evaluated and a new systematic classification of basic reactions was proposed.In the new classification,all the chemical reactions were divided into oxidation-reduction reactions and non-oxidation-reduction reactions,and both can be divided into combination reaction,decomposition reaction and replacement reaction,respectively.In addition,a new class of basic reactions,the complicated decomposition reaction,was appended to reaction system.     

不对称Henry反应的研究进展

总结了各种能有效催化不对称Henry反应的新方法、新条件和新催化剂,讨论了一类拓展的不对称催化Henry反应。对立体选择性催化Henry反应的催化剂的发展提出了作者的一些看法。参考文献26篇。     

A novel modified baylis-hillman reaction of propiolate

A new reaction of propiolates and aldehydes mediated by DABCO analogous to the Baylis-Hillman reaction is described. This reaction provided novel beta-functionalized Baylis-Hillman products and a new methodology for the generation of alkylidene carbene species.     

A new reaction for the direct conversion of 4-azido-4-deoxy-D-galactoside into a 4-deoxy-D-erythro-hexos-3-ulose

[reaction: see text] A new one-step reaction has been developed for converting 4-azido-4-deoxy-d-galactoside into 4-deoxy-d-erythro-hexos-3-ulose by phosphoramidites and tetrazole. It is proposed that the new reaction proceeds via an intramolecular Staudinger reaction of the phosphite intermediate and a tetrazole-catalyzed elimination reaction of the resultant phosphorimidate. Tetrazole appears to be playing a unique role by acting as a bifunctional catalyst to facilitate the elimination reaction.     

New opinions on the amidoalkylation of hydrophosphorylic compounds

A new and milder version of the procedure for the synthesis of N-protected α-aminoalkylphosphorylic compounds by reaction of alkyl carbamates, aldehydes and hydrophosphorylic compounds in acetic anhydride/acetyl chloride and a new mechanism for this type of reaction are described. The isolation, for the first time, of N,N′-benzylidene- and N,N′-alkylidenebiscarbamates as intermediates from the reaction medium and studies of the direct reaction of pre-obtained biscarbamates and hydrophosphorylic compounds in acetic anhydride are reported. A new version of the mechanism for this reaction which includes an Arbuzov-type reaction is proposed.     

Integration of capacity fading in an electrochemical model of Li-ion batteries

We have developed a new method to describe a fading model integrated with a parasitic reaction of rechargeable Li-ion batteries in the present work. In our work, the Li-ion battery reactions and the parasitic reaction are incorporated into one model. A new governing equation and a new field variable are presented in the new model to characterize the parasitic reaction and the relationship to the battery fading. Due to the new variations, the parameters that are changed with the battery’s aging are able to be calculated and updated automatically in the model. The parasitic reaction is assumed to obey a Tafel equation. The simulating results show that the distribution of overpotential of the parasitic reaction as function of x shapes, a figure close to a “V,” suggests the nonuniform distribution of the parasitic current. The parasitic reaction’s equilibrium potential is proved to be one of most important factors that determine the rate of the reaction. In addition, the cutoff charging state of charge (SOC) has a large influence on the parameters related to the rate of the parasitic reaction. Therefore, controlling the charging SOC can be seen as an effective method to protect the battery from aging.     

PdCl2-catalyzed cross-coupling reaction of arylacetylene iodides with arylboronic acids to diarylacetylenes

A new Suzuki-type cross-coupling reaction between 1-iodo-2-arylalkynes and arylboronic acids to afford a wide variety of functionalized diarylacetylenes in a mild reaction condition was developed. The reaction was catalyzed by a small amount of a structurally simple, commercially available, and stable PdCl₂. This unique sp-sp² carbon-carbon bond formation provides a new protocol for the synthesis of diarylacetylenes, which is a new addition to the Suzuki cross-coupling reaction.     

Titanium(IV)-promoted Mukaiyama aldol-Prins cyclizations

[reaction: see text] A new version of the Mukaiyama aldol-Prins (MAP) cyclization has been developed. Unsaturated enol ethers such as 3 were found to couple with aldehydes in the presence of TiBr(4) to give 4-bromotetrahydropyran products. This cascade reaction sequence leads to the formation of two new carbon-carbon bonds, a ring, and three new stereogenic centers. We expect this reaction to be a powerful new tool in synthesis.     

有机化学反应中间体的质谱分析

有机化学反应中活性中间体的性质各异,对反应中间体的表征和研究对于阐明和确证反应机理、优化反应条件、筛选催化剂和发现新类型反应至关重要.近年来,质谱技术和在线微量采样技术的发展,极大程度地拓展了质谱学在该领域的应用.本文总结了近年来本领域发展的新策略、技术和方法,以及有机质谱技术在反应中间体研究中的应用.     

Regioselective TfOH-mediated hydroamidation of ynamides with nitriles

A new TfOH-mediated reaction of ynamides with nitriles as nucleophiles has been developed. The reaction works efficiently under mild reaction conditions to afford a new class of α-acylaminoenamides readily via the intermediacy of keteniminium ion. The reaction displays generality and a broad substrates scope. Additionally, the α-acylaminoenamides could be transformed to highly substituted pyridine, 4-aminopyrimidine or isoquinoline cores.     

Three-component coupling reaction and cyclization of N-tosylimines and TMS-substituted propiolate mediated by DABCO

A new three-component coupling reaction of methyl 3-trimethylsilylpropiolate, N-tosylimine, and tosylamide mediated by DABCO was developed. This reaction was based on the consecutive alpha- and beta-activation method of propiolate involving intramolecular silyl migration previously developed by our group. On the basis of these results, a new cyclization reaction was designed to find a chromene-forming reaction utilizing salicyl N-tosylimine as a bifunctional substrate.     

A Three‐Component Enantioselective Cyclization Reaction Catalyzed by an Unnatural Amino Acid Derivative

A new diastereo‐ and enantioselective three‐component cyclization reaction is described. The reaction takes place between a ketone, a carboxylic acid, and a nitroalkene to yield a bicyclic octahydro‐2H‐indol‐2‐one scaffold possessing three chiral centers. This reaction involves a rearrangement of the nitro group under simple thermal conditions. A plausible mechanism is proposed for this new reaction based on DFT calculations and isotope‐labeling experiments. A new concise enantioselective synthesis of the alkaloid (+)‐pancracine is presented as an example of the potential of this novel organocatalytic cyclization reaction in the synthesis of natural products.     

Superstructure searching algorithm for generic reaction retrieval

Chemical reaction knowledge is usually summarized and retrieved by chemists from references, journals, and reaction databases. To rigorously extract chemical reaction knowledge from large data sets, computer algorithms become much more important. This paper presents a new approach, superstructure searching (SSS) algorithm, for generic reaction retrieval. The algorithm considers all known reaction patterns from the targeted structure and assigns synthetic routes for new chemical compounds. This algorithm consists of screening, atom-by-atom comparison, and computation of R-groups' similarity.     

Highly Diastereoselective and Regioselective Copper‐Catalyzed Nitrosoformate Dearomatization Reaction under Aerobic‐Oxidation Conditions

An unprecedented copper‐catalyzed acylnitroso dearomatization reaction, which expands the traditional acylnitroso ene reaction and acylnitroso Diels–Alder reaction to a new type of transformation, has been developed under aerobic oxidation. Intermolecular and intra‐/intermolecular reaction modes demonstrate an entirely different N‐ or O‐acylnitroso selectivity. Hence, we can utilize this reaction as a highly diastereoselective access to a series of new pyrroloindoline derivatives, which are important structural motifs for natural‐product synthesis.     

金属参与的水相烯丙基化反应

近30年来,水介质中碳-碳键的形成一直是研究的热点,其优越性也逐渐被人们所认知。在已发现的水相金属有机反应中,水相烯丙基化反应是研究得较多和较深入的反应之一。水相烯丙基化反应由于其发展速度较快,新的金属及金属体系参与的烯丙基化反应以及水相烯丙基化反应的机理研究不断被报道。本文综述了水相中金属参与烯丙基化反应的最新研究进展,并对新的反应机理作了简要的阐述。     

物理化学实验Belousov-Zhabotinsky(B-Z)反应的新设计

针对现有物理化学实验教材中的“B-Z振荡反应实验”进行了重新设计,加入了基于反应机理的复杂反应动力学数学处理及B-Z反应在分析检测中的应用。新的实验设计使用的仪器、试剂等与原方案相同,在保留原实验趣味性、前沿性的基础上增加了更多的理论知识点,提高了实验的自主性、设计性,加大了实验的难度。在教学模式上新的实验设计更易于课上、课下相结合:课下完成理论模拟探究振荡周期的影响因素,初步确定实验方案(反应条件),课上实施、验证、优化实验设计,并拓展B-Z振荡反应的应用。新实验设计更能加深学生对非线性非平衡态动力学与耗散结构的认识,理解B-Z振荡反应分析检测应用与反应机理间的联系。关于非线性动力学的数学处理方法可以应用于科学研究与生产实践中。     

Tandem Sakurai-aldol addition reactions as a route to structurally complex carbocycles

Tandem intramolecular Sakurai-aldol reactions provide a concise and highly diastereoselective route to substituted cyclohexenone derivatives. The cyclization substrates are readily obtained using olefin isomerization-Claisen rearrangement (ICR) reactions to prepare the key chiral allyl silane precursors. The Claisen reaction products are elaborated to the chiral Sakurai-aldol substrates by an efficient two-step sequence involving vinyl organometallic-aldehyde addition and oxidation of the resulting alcohol. The reaction of the resulting enones with TiCl(4) elicits a highly stereoselective allyl silane conjugate addition to produce a trichlorotitanium enolate as the reaction intermediate; intermolecular trapping of the enolate with an aldehyde provides pentasubstituted cyclohexanone derivatives in which the annulation reaction establishes four stereocenters and two new C-C bonds. A fully intramolecular variant of the Sakurai-aldol reaction that creates four stereocenters, two new C-C bonds, and establishes two new carbocyclic rings is also described.     

Tandem Diels-Alder/fragmentation approach to the synthesis of eleutherobin

[reaction: see text] A synthesis of 28, the carbon framework of the eleutherobin aglycone, is reported in a 15-step sequence from readily available starting materials. The tandem Diels-Alder reaction of 6 and 7 to produce 18, in which three new rings and six new stereocenters are formed, is a key step in the reaction sequence.     

Protecting Groups for Thiols Suitable for Suzuki Conditions

The thiol group is one of the few groups NOT tolerated by the Suzuki reaction. Therefore, a new protective group, the 2-methoxyisobutyryl group, was developed by tuning the electronic/steric properties of the acyl residue. Other thioesters, such as thioacetate, result in a more or less dominant side reaction, which to date has not been described: sulfur-assisted acylation of boronic acids. The reaction pathway for this new reaction is discussed.