烯胺酮α-官能团化反应的研究进展

烯胺酮是一类非常重要的有机合成砌块,具有易获得、储存方便、反应多样性等优点.更重要的是,烯胺酮是许多杂环化合物的重要前体.最近,通过C—H活化对烯胺酮进行过渡金属催化或无过渡金属的α-官能团化反应已成为构建官能化烯胺酮或杂环化合物的一种更为原子和步骤经济的策略,并引起了许多有机化学家的关注.根据成键类型,该综述分为五个部分:C—C键的形成、C—O键的形成、C—N键的形成和C—X键的形成以及C—S/C—Se键的形成.主要对烯胺酮α位官能团化反应进行了综述,从反应机理、反应体系、底物范围等角度系统地综述了烯胺酮α位官能团化反应的进展.     

有机硅试剂参与过渡金属催化的C-H官能团化反应形成C-C键的研究进展

作为一类重要的有机金属试剂,有机硅试剂在有机合成化学的C—C键形成中得到了广泛应用.综述了近年来有机硅试剂参与的过渡金属催化下C—H官能团化反应形成C—C键的研究进展,重点介绍了Pd催化下C—H官能团化的Hiyama偶联反应.     

过渡金属催化重氮化合物参与的芳烃碳(sp~2)-氢键官能团化研究进展

碳-氢键官能团化已经成为化学中最重要的研究课题之一.控制碳-氢键官能团化的区域选择性在目前是最关键的问题,同时也很具有挑战性.过渡金属催化的重氮化合物的有机转化,例如杂-氢键插入、环丙烷化、交叉偶联反应以及烷基碳-氢[C(sp~3)—H]键官能化反应发展比较成熟,但是芳烃的碳-氢[C(sp~2)—H]键官能团化反应研究较少.这篇综述总结了过渡金属催化重氮化合物参与的芳烃的碳-氢[C(sp~2)—H]键官能团化反应研究进展.为了实现反应的选择性,有两种策略运用在其中.一种是导向的碳-氢(C—H)键活化,主要得到邻位碳-氢键官能团化产物;另外一种是非导向策略,主要表现出对位选择性.对一些代表性的例子也做了机理介绍.     

光诱导铁催化在有机合成中的应用研究进展

近年来,以过渡金属钌和铱络合物为代表的光催化剂的开发和应用为有机合成开启了新篇章,这些过渡金属光催化剂参与的光催化反应为化学键的构筑和有机转化提供了温和高效的新策略.为了丰富光催化剂的种类,拓宽光催化体系的适用范围,发展绿色可持续化学,近年来一些廉价易得的过渡金属比如铜、铁等被相继开发用作光催化剂.其中,铁催化剂因其无毒、种类丰富,并且具有独特的配体-金属电荷转移性质,在光催化合成领域大放异彩.依据反应类型对光诱导铁催化反应进行了综述,主要包括C—H键官能团化反应、C—C键官能团化反应、烯烃双官能团化反应、交叉偶联反应、脱羧官能团化反应、选择性氧化和还原反应.     

基于C—H键官能团化的药物合成

过渡金属催化的C—H键官能团化是有机化学的重要研究内容,并被作为工具广泛应用于药物合成领域。本文阐述了C—H键官能团化的经典反应类型,着重综述了C—H键的芳基化、烯基化、烷基化、卤化、羟基化、胺化和C—H插入反应在药物合成中的应用,详细描述了具体药物的合成实例,并对重要的反应机理进行了分析,最后展望了C—H键官能团化在药物合成中的发展前景。     

光促进十聚钨酸盐催化的C—H键官能团化反应

近年来,十聚钨酸盐作为催化剂在光催化有机合成领域引起了广泛关注.在光照下,十聚钨酸盐可以活化反应物中的C—H键,通过"氢原子转移"作用产生自由基,进而实现C—H键官能团化反应.对近年来十聚钨酸盐在光诱导下催化C—H键官能团化,构筑C—C、C—N、C—F键等的研究进展进行了综述.     

Cs2CO3辅助钯催化X—H (X=C、O、N、B)官能团化反应的理论计算研究

钯催化X—H (X=C、O、N、B)官能团化反应是重要的有机合成策略,能以芳基卤化物、烯类或炔类等小分子化合物为底物,以原子经济的方式构建C—C和C—X (X=O、N、B)键。其中,Cs₂CO₃辅助钯催化X—H (X=C、O、N、B)官能团化反应因具有反应性好、产率高、底物适用范围广等优点,成为近年来有机合成领域的关注热点之一,在构建含C—C和C—X键的多环天然产物骨架方面起着重要作用。采用DFT理论研究Cs₂CO₃辅助钯催化X—H (X=C、O、N、B)官能团化反应,能帮助人们从微观层面了解该类反应的实质,进而为设计新的实验合成路线提供启示。本文对近十年来Cs₂CO₃辅助钯催化X—H (X=C、O、N、B)官能团化反应的最新理论研究进展进行分类和总结,对反应的微观机理以及Cs₂CO₃在反应中的作用机制进行了深入探讨,并对该领域的现存问题和发展前景进行了总结与展望。     

铑催化3-重氮吲哚-2-亚胺与吡唑啉酮的C—H官能团化反应制备3-吡唑基吲哚（英文）

报道了一种在Rh2(OAc)4存在下α-亚胺卡宾和吡唑啉酮的高效C—H官能团化反应.该方法通过C—C键的形成为构建结构多样的3-吡唑基吲哚化合物提供了一种快速、直接的途径,反应具有中等至优异的产率和良好的官能团耐受性.     

通过对映选择性质子化实现吲哚的不对称C—H官能团化反应研究

研究了醋酸铑[Rh2(OAc)4]与手性磷酸共催化的芳基重氮乙酸酯对吲哚化合物的不对称C—H官能团化反应,通过对吲哚C—H官能团化反应质子转移机制的研究,提出了通过不对称质子化实现金属卡宾与吲哚的C—H不对称官能团化反应的新策略.通过吲哚C—H官能团化反应氘代实验证明,在金属卡宾对N-烷基吲哚的碳氢官能团化中,质子迁移是一个分子间的反应,需要借助一个"质子梭"试剂完成,因此通过应用"手性质子梭"催化的不对称质子化有望实现反应的对映选择控制.通过选用手性磷酸作为"手性质子梭"实现了吲哚C—H官能团化反应的不对称催化,重氮化合物在醋酸铑的催化下形成金属卡宾,金属卡宾与吲哚反应生成潜手性的离子对中间体,在催化剂量的手性磷酸存在下,质子迁移通过双功能的手性磷酸完成,通过手性磷酸对潜手性的离子对中间体的不对称质子化实现了反应的对映选择性控制.反应给出了优秀的产率(最高可达99%),良好到优秀的对映选择性(最高可达94%ee),且此反应对其他N-芳基和N-硅基吲哚也有良好的反应兼容性.     

木质素二聚体模型物裂解历程的理论研究

木质素作为生物质的主要成分之一, 是生物油的重要组分, 在工业生产中有着重要的应用. 生物质高温裂解液化制备生物油的过程伴随着木质素的裂解, 因此研究木质素高温裂解历程, 对生物油的制备有很大的帮助. 利用密度泛函方法对木质素在高温条件下的裂解历程进行理论研究, 并通过对各步反应的热力学焓变计算, 确定了初次裂解的路径为Cα—Cβ和β-O-4热裂解路径. 根据进一步的研究预测了裂解反应的主要产物.     

两种新稀土双核配合物的合成、表征及其对磷酸二酯键模型物（BDNPP）和DNA的作用研究

合成和表征了两种新的双核配合物[Eu_2 (bbimp) (CH_3COO) (CH_3CH_2O)_2 (CH_3CH_2OH)] (ClO_4)_2 (A)和[Nd_2 (bbimp)-(CH_3COO) (CH_3CH_2O)_2 (CH_3CH_2OH)] (ClO_4)_2 (B)。用紫外光谱法分别研究了磷酸二酯键模型物双-（ 2，4-二硝基苯基）磷酸盐（BDNPP）与配合物（A，B）的水解动力学反应。当 BDNPP与A，B的浓度均为2.5 * 10~(-5) mol/L时，反应为二级反应；在25 ℃，pH 7.26时，二级水解速率常数分别为2479 (mol/L)~(-1)·min~(-1)，1678 (mol/L) ~(-1)·min~(-1)，半衰期分别为16.1 min和23.8 min，比单独的Eu~(3+)，Nd~ (3+)水解BDNPP的速率均快得多，37 ℃时反应更快；在25 ℃，pH 6.50～8.50时， 两个反应的水解速率常数的lgK与pH值均呈正的线性关系。两种配合物与小牛胸腺 （CT）DNA作用，使CT DNA最大吸收峰发生减色和红移，使溴化乙锭（EB）-DNA复 合物体系荧光强度减弱。两种配合物对超螺旋质粒pBR322 DNA的断裂在50 ℃，pH 8.0时，效果最好。     

带双键侧链的二氧化碳三元共聚物的合成及性能研究

二氧化碳和环氧丙烷共聚物的玻璃化温度处于35～40℃,在低于20℃的环境下脆性很大.在稀土三元催化剂Y(CCl3COO)3ZnEt2甘油(glycerine)下实现了CO2、环氧丙烷(PO)和烯丙基缩水甘油醚(AGE)的三元共聚,合成了侧链带双键的二氧化碳共聚物,其玻璃化温度(Tg)为-15.4～36.1℃,大幅度拓展了二氧化碳共聚物的低温区使用范围.     

β-丙醇酸内酯气相热分解反应的过渡态——从头计算法研究

本文用量子化学从头计算法研究了β-丙醇酸内酯热分解反应的机理。对均相热分解的两种可能方式进行了自洽场分子轨道法研究(3-21G基组):C_2H_4+CO_2(1)←CH_2—C—O—CH_2→(2)CH_2=C=O+H_2CO反应物、产物和过渡态的几何构型分别用能量梯度法进行了优化, 并对能量做了二级微扰能(MP2)的校正。用这种方法得出反应(1)的活化势垒为166.0 kJ mol~(-1), 反应(2)的话化势垒为302.0 kJ mol~(-1)。计算结果表明: 在一般温度下, 热分解反应主要以反应(1)的机理进行。这个结论与动力学的实验结果是一致的。     

Cationic Rh complexes with novel spiro tetraarylpentaborate anions prepared from arylboronic acids and aryloxorhodium complexes

Ar-B(OH)2 (1a: Ar = C6H4OMe-4, 1b: Ar = C6H3Me2-2,6) react immediately with Rh(OC6H4Me-4)(PMe3)3 (2) in 5 : 1 molar ratio at room temperature to generate [Rh(PMe3)4]+[B5O6Ar4]- (3a: Ar = C6H4OMe-4, 3b: Ar = C6H3Me2-2,6). p-Cresol (92%/Rh), anisole (80%/Rh) and H2O (364%/Rh) are formed from 1a and 2. The reaction of 1a with 2 for 24 h produces [Rh(PMe3)4]+[B5O6(OH)4]- (4) as a yellow solid. This is attributed to hydrolytic dearylation of once formed 3a because the direct reaction of 3a with excess H2O forms 4. An equimolar reaction of 2 with phenylboroxine (PhBO)3 causes transfer of the 4-methylphenoxo ligand from rhodium to boron to produce [Rh(PMe3)4]+[B3O3Ph3(OC6H4Me-4)]- (5). Arylboronic acids 1a and 1b react with Rh(OC6H4Me-4)(PR3)3 (6: R = Et, 8: R = Ph) and with Rh(OC6H4Me-4)(cod)(PR3) (11: R = iPr, 12: R = Ph) to form [Rh(PR3)4]+[B5O6Ar4]- (7a: R = Et, Ar = C6H4OMe-4, 7b: R = Et, Ar = C6H3Me2-2,6, 9a: R = Ph, Ar = C6H3Me2-2,6) and [Rh(cod)(PR3)(L)]+[B5O6Ar4]- (13b: R = iPr, L = acetone, Ar = C6H3Me2-2,6, 14a: R = Ph, L = PPh3, Ar = C6H4OMe-4, 14b: R = Ph, L = PPh3, Ar = C6H3Me2-2,6), respectively. Hydrolysis of 14a yields [Rh(cod)(PPh3)2]+[B5O6(OH)4]- (15) quantitatively.     

合成气转化为乙醇的反应机理

本文在助剂型Rh催化剂上采用了以CH_2OD、D_2~(18)O为捕获剂的原位化学捕获反应, 以及以D_2~(18)O为重氧源试剂的原位氧同位素交换反应, 对合成气转化为乙醇的反应机理进行了研究。在原位捕获反应中检测到CH_2DCOOCH_3、CH_3COOCH_3和CH_2DCOOD、CH_3COOD的生成, 表明合成乙醇反应过程中存在中间体乙烯酮和乙酰基, 当CH_3OD/H_2比值足够大时主要捕获到CH_2DCOOCH_3, 说明乙酰基主要由乙烯酮的部分氢化反应生成。原位氧同位素交换反应检测到含~(18)O的乙醇、乙醛、乙酸的生成, 表明乙烯酮等C_2-含氧化合物前驱怵与重氧水发生了氧同位素交换反应。籍此, 无须如Katzer等人那样假设乙烯酮互变异构为位能较商的环氧乙烯而后进行氧同位素交换, 就可以得到Katzer等人在~(13)C~(16)O/~(13)C~(18)O+H_2反应中观察到的产物乙醇的同位素组成结果。本文的实验结果进一步说明我们提出的“CO缔合—卡宾—乙烯酮—乙酰基—乙醇(醛)”机理是合理的。     

Infrared predissociation spectroscopy of M+ (C6H6)(1-4)(H2O)(1-2)Ar(0-1) cluster ions, M = Li, Na

Infrared predissociation (IRPD) spectra of Li(+)(C(6)H(6))(1-4)(H(2)O)(1-2)Ar(0-1) and Na(+)(C(6)H(6))(2-4)(H(2)O)(1-2)Ar(1) are presented along with ab initio calculations. The results indicate that the global minimum energy structure for Li(+)(C(6)H(6))(2)(H(2)O)(2) has each water forming a π-hydrogen bond with the same benzene molecule. This bonding motif is preserved in Li(+)(C(6)H(6))(3-4)(H(2)O)(2)Ar(0-1) with the additional benzene ligands binding to the available free OH groups. Argon tagging allows high-energy Li(+)(C(6)H(6))(2-4)(H(2)O)(2)Ar isomers containing water-water hydrogen bonds to be trapped and detected. The monohydrated, Li(+) containing clusters contain benzene-water interactions with varying strength as indicated by shifts in OH stretching frequencies. The IRPD spectra of M(+)(C(6)H(6))(1-4)(H(2)O)(1-2)Ar are very different for lithium-bearing versus sodium-bearing cluster ions emphasizing the important role of ion size in determining the most favorable balance of competing noncovalent interactions.     

Cu/WO3-NiO上光促表面催化二氧化碳与水合成甲醇反应的规律

 采用溶胶－凝胶法制备了n－p复合半导体材料0．75％Cu／WO3－1．5％NiO，用X射线衍射、透射电镜、红外光谱、紫外－可见光漫反射和程序升温脱附等技术对材料结构、吸光性能和化学吸附性能进行了表征，研究了该材料对CO2与H2O合成CH3OH的光促表面催化反应(PSSR）规律．结果表明：所制备的材料明显有利于促进目的反应，室温条件下就有CH3OH生成，选择性超过90％，升高反应温度可提高CH3OH产量，且选择性仍高于88％．根据实验结果，得出CO2在材料表面的卧式吸附态为CH3OH的前驱物，并对PSSR机理进行了讨论．     

Absolute rate coefficient of the OH + CH(3)C(O)OH reaction at T = 287-802 K. The two faces of pre-reactive H-bonding

The rate constants for the reaction OH + CH3C(O)OH --> products (1) were determined over the temperature range 287-802 K at 50 and 100 Torr of Ar or N2 bath gas using pulsed laser photolysis generation of OH by CH3C(O)OH photolysis at 193 nm coupled with OH detection by pulsed laser-induced fluorescence. The rate coefficient displays a complex temperature dependence with a sharp minimum at 530 K, indicating the competition between a reaction proceeding through a pre-reactive H-bonded complex to form CH3C(O)O + H2O, expected to prevail at low temperatures, and a direct methyl-H abstraction channel leading to CH2C(O)OH + H2O, which should dominate at high temperatures. The temperature dependence of the rate constant can be described adequately by k1(287-802 K) = 2.9 x 10(-9) exp{-6030 K/T} + 1.50 x 10(-13) exp{515 K/T} cm3 molecule(-1)(s-1), with a value of (8.5 +/- 0.9) x 10-13 cm3 molecule(-1)(s-1) at 298 K. The steep increase in rate constant in the range 550-800 K, which is reported for the first time, implies that direct abstraction of a methyl-H becomes the dominant pathway at temperatures greater than 550 K. However, the data indicates that up to about 800 K direct methyl-H abstraction remains adversely affected by the long-range H-bonding attraction between the approaching OH radical and the carboxyl -C(O)OH functionality.     

High-temperature shock tube measurements of methyl radical decomposition

We have studied the two-channel thermal decomposition of methyl radicals in argon, involving the reactions CH3 + Ar --> CH + H2 + Ar (1a) and CH3 + Ar --> CH2 + H + Ar (1b), in shock tube experiments over the 2253-3527 K temperature range, at pressures between 0.7 and 4.2 atm. CH was monitored by continuous-wave, narrow-line-width laser absorption at 431.1311 nm. The collision-broadening coefficient for CH in argon, 2gamma(CH-Ar), was measured via repeated single-frequency experiments in the ethane pyrolysis system behind reflected shock waves. The measured 2gamma(CH-Ar) value and updated spectroscopic and molecular parameters were used to calculate the CH absorption coefficient at 431.1311 nm (23194.80 cm(-1)), which was then used to convert raw traces of fractional transmission to quantitative CH concentration time histories in the methyl decomposition experiments. The rate coefficient of reaction 1a was measured by monitoring CH radicals generated upon shock-heating highly dilute mixtures of ethane, C2H6, or methyl iodide, CH3I, in an argon bath. A detailed chemical kinetic mechanism was used to model the measured CH time histories. Within experimental uncertainty and scatter, no pressure dependence could be discerned in the rate coefficient of reaction 1a in the 0.7-4.2 atm pressure range. A least-squares, two-parameter fit of the current measurements, applicable between 2706 and 3527 K, gives k(1a) (cm(3) mol(-1) s(-1)) = 3.09 x 1015 exp[-40700/T (K)]. The rate coefficient of reaction 1b was determined by shock-heating dilute mixtures of C2H6 or CH3I and excess O2 in argon. During the course of reaction, OH radicals were monitored using the well-characterized R(1)(5) line of the OH A-X (0,0) band at 306.6871 nm (32606.52 cm(-1)). H atoms generated via reaction 1b rapidly react with O2, which is present in excess, forming OH. The OH traces are primarily sensitive to reaction 1b, reaction 9 (H + O2 --> OH + O) and reaction 10 (CH3 + O2 --> products), where the rate coefficients of reactions 9 and 10 are relatively well-established. No pressure dependence could be discerned for reaction 1b between 1.1 and 3.9 atm. A two-parameter, least-squares fit of the current data, valid over the 2253-2975 K temperature range, yields the rate expression k(1b) (cm(3) mol(-1) s(-1)) = 2.24 x 10(15) exp[-41600/T (K)]. Theoretical calculations carried out using a master equation/RRKM analysis fit the measurements reasonably well.     

Synthesis and Crystal Structure of a Heterometallic Chain Coordination Polymer:{[Ni_2Mn_2L_2(CH_3CH_2OH)(H_2O)]·CH_3OH·2H_2O}_n

A chain-like coordination polymer with the chemical formula of {[Ni2Mn2L2(CH3CH2OH)-(H2O)]·CH3OH·2H2O}n has been synthesized by the assembly reaction of K2NiL·H2O and Mn(OAC)2·4H2O with a 1:1 mole ratio in methanol,where OAC-=CH3COO-and H4L=2-hydroxy-3-[(E)-({2-[(2-hydroxybenzoyl)imino]ethyl}imino)methyl]benzoic acid.The crystal structure was determined by single-crystal X-ray diffraction analysis.It belongs to the triclinic system,space group P1,with a=9.9464(8),b=13.4718(11),c=14.3877(12),α=87.1930(10),β=85.4280(10),γ=74.6470(10)°,V=1852.4(3)3,Z=2,Dc=1.807g/cm3,Mr=1008.03,λ(MoKα)=0.71073,μ(MoKα)=1.794 mm-1,F(000)=1032,R=0.0527 and wR=0.1284(Ⅰ2σ(Ⅰ)).The compound exhibits a chain-like structure formed by dissymmetrical tetranuclear units.