钯催化芳基偶氮的氧化羰基化反应（英文）

采用TBHP作为氧化剂,发展了钯催化芳基偶氮化合物N=N双键断裂的氧化羰基化反应.芳基偶氮的羰基化反应在Pd(OAc)2(5%),MeO-BIPHEP(5%),芳基偶氮(0.2 mmol),TBHP(2 equiv),H2O(1 equiv),DCE(1 mL),CO(3.0 MPa)的条件下110℃反应12 h后,经柱层析纯化分离得到31%-91%的芳基脲.初步的机理研究表明,芳基偶氮化合物的N=N双键断裂原位产生芳基胺,再进一步氧化羰基化生成芳基脲.     

高分子负载钯基双金属催化苯胺氧化羰基化反应

芳香族氨基甲酸酯(ArNHCO₂R)是制备芳基异氰酸酯(ArNCO)的重要中间体,其合成通常需用光气与芳胺反应,且生成大量HCl.因此,人们致力于发展一些无需光气参与的反应过程,如催化芳胺氧化羰基化生成芳氨基甲酸酯.     

钯催化胺的羰基化反应

综述了钯催化胺的单，双羰基化反应以及钯催化胺基化反应工业及有机合成中的应用，同时对羰基化反应新进展－超临界二氧化碳流体作为反应介质也作了综述。     

钯催化苯酚氧化羰基化合成碳酸二苯酯反应机理的研究进展

综述了Pd2 催化苯酚氧化羰基化合成碳酸二苯酯反应机理的最新研究进展,详细介绍了对催化机理的验证和如何实现Pd催化体系的高效循环.苯酚氧化羰基化合成碳酸二苯酯催化机理的研究表明,碳酸二苯酯是通过CO对Pd-O键的插入和中间体Pd(COOPh)(OPh)的还原消除而生成的.在Pd催化剂体系中引入配体和氧化还原助剂,能防止Pd0的聚集,提高Pd0再生为活性Pd2 的速率,加速催化循环.分析总结了Pd催化剂体系目前存在的问题,并提出了催化剂体系的研究方向.     

超临界二氧化碳介质中钯催化炔烃羰基化反应

研究了以超临界二氧化碳为反应介质实现改善钯催化炔烃羰基化反应绿色性的方法 .研究结果表明 :醇的用量、二氧化碳压力和反应温度等因素均对钯催化炔烃羰基化反应的化学选择性均有影响 ,即存在炔烃的羰基化反应与氧化偶合反应的竞争     

钯催化气相氧化羰基化合成碳酸二甲酯

通过催化剂反应性能和反应前后XPS谱图对比，分析了负载型钯催化剂在甲醇气相氧化羰基化合成碳酸二甲酯过程中的失活原因，研究了HCl在维持催化剂活性及失活催化剂再生中的作用．结果表明，氯离子的流失是负载型钯碳催化剂失活的主要原因．由于氯离子的流失，对于PdCl2／AC催化剂，钯很容易从二价变为零价：对于PdCl2-CuCl2／AC催化剂，CuCl2发生变化，失去使钯保持二价氯化物状态的功能．在反应过程中补充HCl可以延长催化剂的寿命，也可以利用HCl对失活催化剂进行再生，但采用HCl不能从根本上解决催化剂失活的问题．     

胺氧化羰基化合成脲的研究进展

CO是一种廉价、丰富且有用的C1分子,将其作为羰基源参与胺氧化羰基化反应是有机化学中一类重要的反应.近年来,采用胺氧化羰基化合成脲类化合物的技术路线备受关注.我们综述了催化剂参与的胺氧化羰基化合成脲类化合物的研究现状,还对胺氧化羰基化反应的发展趋势进行了展望.     

钯催化的酰胺羰基化反应

酰胺羰基化的发现为氨基酸及其衍生物的合成提供了一个新方法。该合成方法 步骤简洁，只需一步即可从醛、酰胺-氧化碳合成N-酰基氨基酸，而且该反应是原 子经济型反应。与钴催化的酰胺羰基化相比，钯催化的反应条件更为温和，催化效 率也大为提高，对基团有更广普的适应性。简述近所来这一领域的新进展。     

钯催化炔烃羰基化反应新进展

综述了过渡金属钯催化的炔烃羰基化反应最新研究进展，深入讨论了影响钯催 化的炔烃碳基化反应的区域选择性和立体选择性的两大因素：溶剂效应与酸碱效应。     

高价碘试剂促进的N-芳基磺酰胺类化合物脱芳基反应（英文）

通过高选择性惰性磺酰胺芳基C—N键裂解反应,发展了一种Dess-Martin氧化剂(DMP)促进的N-芳基磺酰胺的脱芳基的方法.该无金属参与的反应在温和的条件下进行,可提供各种在生物学上有重要应用价值的伯磺酰胺类化合物,其中某些磺酰胺使用传统的氨解和水解方法难以获得.这一简单有效的脱芳基反应可在无金属催化剂条件下使芳基作为磺酰胺类化合物的氨基保护基.     

C=C Bond Oxidative Cleavage of BODIPY Photocages by Visible Light

Photocages for protection and the controlled release of bioactive compounds have been widely investigated. However, the vast majority of these photocages employ the cleavage of single bonds and high-energy ultraviolet light. The construction of a photoactivation system that uses visible light to cleave unsaturated bonds still remains a challenge. Herein, we report a regioselective oxidative cleavage of C=C bonds from a boron-dipyrrolemethene (BODIPY)-based photocage by illumination at 630 nm, resulting in a free aldehyde and a thiol fluorescent probe. This strategy was demonstrated in live HeLa cells, and the generated α-formyl-BODIPY allowed real-time monitoring of aldehyde release in the cells. In particular, it is shown that a mannose-functionalized photocage can target HepG2 cells.     

A Dimeric Chromium(II) Pincer as an Electron Shuttle for N=N Bond Scission

Reduction of the bis-pyrazolyl pyridine complex [CrL]₂ with 4 KC₈, followed by addition of one azobenzene (overall mole ratio 1:4:1), PhNNPh, transfers reducing equivalents to three azobenzenes, to form [K₃Cr(PhNNPh)₃]. This has three κ² PhNNPh²⁻ ligands and K⁺ bound to nitrogen atoms of azobenzene. When the stoichiometry is modified to 1:4:3, the product is changed to [K₂CrL(PhNNPh)₂], which has C₂ symmetry except for the intimate ion pairing of two K⁺ ions to reduced azobenzene nitrogen atoms, and to pyrazolate and phenyl rings. The origin of the observed delivery of reducing equivalents to several, not to a single N=N bond, is traced to the resistance of the one-electron-reduced substrate to receiving a second electron, and is thus a general phenomenon. [CrL]₂ alone is shown to be a two-electron reductant towards benzo[c]cinnoline (BCC) resulting in a product of formula [Cr₂L₂(BCC)], in which the reducing equivalents originate purely from Cr^II. An analogous study of the reaction of [CrL]₂ with azobenzene yields [Cr₂L₂(PhNNPh)(THF)], an adduct in which one THF has displaced one of four hydrazide nitrogen/Cr bonds. Together these illustrate different modes for the Cr₂L₂ unit to bind and reduce the N=N bond. Collectively, these results show that two divalent Cr, without added K⁰, have the ability to reduce the N=N bond. Further KC₈ reduction of preformed Cr₂L₂(RNNR) inevitably gives products in which K⁺ stabilizes the charge in the increasingly electron-rich nitrogen atoms, in a phenomenon which mimics proton coupled electron transfer: K⁺ performs the role of H⁺. A least-squares fit of the two singly reduced DFT structures shows that the only major change is a re-orientation of one of the two phenyl rings in order to avoid repulsion with potassium but to still allow interaction of that phenyl π system with K⁺. This shows both the impact of K⁺, being modest to nitrogen/chromium interactions, but nevertheless accommodating some π donation of phenyl to potassium. Finally, delivering increasing equivalents of KC₈ leads to complete cleavage of the N=N bond, and both N bind to three Cr^II. The varied impacts of the K⁺ electrophile on NN multiple bond reduction is discussed.     

Selenium-Catalyzed Oxidative Carbonylation of Aniline and Alcohols to N-Phenylcarbamates

A facile one-pot, phosgene-free synthesis of N-phenylcarbamates is demonstrated. Catalyzed by selenium, oxidative carbonylation of aniline with alcohols in the presence of carbon monoxide and oxygen affords the corresponding N-phenylcarbamates, mostly in fair to good yields. Selenium can be easily recovered because of its phase-transfer catalysis function.     

Amine‐Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation

A sensitive amine‐responsive disassembly of self‐assembled Au^I‐Cu^I double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)₂][CuI₂] revealed the contribution of Cu‐assisted ligand exchange of N‐heterocyclic carbene (NHC) by amine in [Au(NHC)₂]⁺ and the capacity of [CuI₂]^? on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d¹⁰ metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates.     

碳-氟键断裂用于构建氟代异噁唑化合物

含氟异噁唑骨架是许多药物及农药分子中的重要结构单元,其中单氟代异噁唑类化合物的合成方法还比较有限.从易得的α-三氟甲基-β-羰基酯出发,发展了基于碱促进的碳氟键断裂策略的氟代异噁唑化合物合成方法,该反应条件温和,操作简便,官能团兼容性良好,可以中等到较好的收率得到一系列3-氟代异噁唑化合物,且所得产物可进一步转化为生物活性分子的类似物.     

N-Heterocyclic Carbene-Palladium Complex Catalyzed Oxidative Carbonylation of Amines to Ureas

Palladium carbene shows high efficiency without any promoter on oxidative carbonylation of amines to ureas and a new type of palladium carbene complex containing both an aniline and an NHC ligands was found to be the active species for the reaction.     

硒催化3,4-二氯苯胺和甲醇氧化羰基化合成灭草灵

报道了一种绿色、简易的合成灭草灵的方法,首次以廉价易得且能循环使用的非金属硒作催化剂,以CO替代剧毒光气作羰基化试剂,通过3,4-二氯苯胺和甲醇经"一锅法"的硒催化氧化羰基化反应来直接合成灭草灵。考察了压力、3,4-二氯苯胺和甲醇用量比、催化剂硒粉用量、溶剂种类、时间、温度及助催化剂种类对反应的影响规律,获得了实施该反应的较优条件。即,在100 mL高压反应釜中:压力3 MPa(n(CO)∶n(O2)=9∶1),3,4-二氯苯胺5 mmol,CH3OH 75 mmol,Se 0.25 mmol,乙酸乙酯10 mL,时间5 h,温度130℃,三乙胺10 mmol。在此条件下,目标产物灭草灵的收率为67%。该方法具有步骤简短、方法绿色和操作方便等优点。     

Pd／C催化剂用于苯胺氧化羰基化

研究了催化剂制备条件、助催化剂对负载型Ｐｄ／Ｃ催化剂性能的影响及氧分压、原料苯胺中硝基苯的加入对苯胺氧化羰基化反应的影响；用Ｘ光电子能谱（ＸＰＳ）、程序升温还原（ＴＰＲ）和现场红外（ＩＲ）表征钯催化剂；根据实验结果提出在Ｐｄ／Ｃ－ＮａＩ催化剂体系、醇介质中，苯胺氧化羰基化可能的反应机理．